Impulse Radial Stirling Turbine

Discussion on Stirling or "hot air" engines (all types)
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airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Impulse Radial Stirling Turbine

Post by airpower »

So who will have the first model of a fast spinning impulse radial Stirling turbine with counter rotating discs operational?
airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Re: Impulse Radial Stirling Turbine

Post by airpower »

https://web.archive.org/web/20151226095 ... /a011.html
Google translate (unfortunate a lot of drawings are missing)

< Menü> <Verzeichnis> <Register>
011

Single-stroke hot gas engine
(or the high-speed single-stroke Stirling engine)

The <two-shaft engine> - the expansion engine points the way to the hot-gas engine, to the <high-speed Stirling engine>. Until now it was not possible to run the cycle in the Stirling engine with practically unlimited speed.

Keeping hot gas available on demand at any pressure and converting it into work is only possible with the single-ended principle.
In the working gas, which is under high pressure, high heat densities are achieved through recuperative combustion. See <Protocol> for <REKU burner>
The working medium can reach high temperatures at high pressures, because the internal sealing of the moving parts is kept constant by the good expansion options in the lower temperature range.
By limiting the engine speed as usual in the Stirling engine, i.e. the heat transfer and cooling rate in the engine need not be taken into account.

Increases in performance through higher speeds are desired, because the engine can then become smaller, thus paving the way for automobile engines. - An automobile engine with primary solid fuel.

The operating gas was then heated in an oversized heat exchanger without going via steam.
The thermal energy of the gas can be stored for several strokes.
The heater is decoupled from the cooler and generates the hot gas on demand - and can be recharged with heat for a short time, regardless of the work cycle.
The single-stroke hot gas engine has two circuits, a cold and a hot circuit. The operating gas can work under high pressure in this closed circuit without the sealing problems that are known from rolling diaphragms.

In this case, the heating may also be carried out with solid fuels, e.g. charcoal.
The heat only generates work in the fully heat-insulated expansion space. The hot gas expands over a variable expansion section, as can be seen on the <270° expansion motor>. Then the exhaust is exhausted and the gases are cooled down in the cooler and create a vacuum on the rear of the rotary piston, which is compressed and fed to the heater heat exchanger as cold gas that is under high pressure.
The work cycle can begin again.

Surprisingly, the conventional Stirling engine is more efficient than the Otto engine, but it never really caught on. It's not just the complicated mechanics and the size of the motor, it's also the rather slow heat transfer that is tied to the RPM.

At this point, the single-stroke hot-gas engine is intended to improve efficiency by allowing the speed to be increased without having to limit the rate of heat transfer over time. For these reasons, the heater can be made extremely large and act as a reservoir.
A special charcoal-fired oven is sufficient for operation, with the benefit of intermittent breaks.
Or for a mobile engine, the hot gas is generated by a relatively small burner with recuperative heating of the burner combustion air. See <Burner> and the <Protocol>.

The conventional four Stirling cycles are shown below as a scheme cycle 1 - 4 Of course, Stirling engines are also built with two cylinders, it's the same principle.
A change occurs when the heat obtained from the external heating can be converted into work more effectively according to the single-ended principle. The Stirling advantages are used in this way, the disadvantages are remedied or do not appear.
One of the advantages is that the single-stroke hot-gas engine works according to the <single-stroke principle>, but the conventional Stirling engine, as the cycle sequence shows, works as a four-stroke engine from 1 - 4. Developing a Stirling engine for specific applications often results in prohibitively complicated designs.

The single-stroke hot gas engine is intended to stop this development. This is possible because this external combustion engine can be built in all sizes and is not tied to a limited speed. In this case, however, the term Stirling engine is not entirely appropriate.
There is an unmistakable relationship to the Stirling engine, but the recuperative combustion and the high heat densities that can be achieved, which act on the rotary pistons in variable expansion, result in a different picture. See <Protocol> for <REKU burner> The working medium may reach high temperatures at high pressures, because the internal sealing of the moving parts is kept constant in the lower temperature range by the good expansion options.
By limiting the engine speed as is usual in the conventional Stirling engine, i.e. the heat transfer and cooling rate in the engine can be used without restriction in the single-stroke hot gas engine.
Increases in performance through higher speeds are also in the Single-stroke hot gas engine desirable, because then the engine can be smaller. The single-stroke hot gas engine can do this too.

The operating gas is heated in an oversized heat exchanger that can store the thermal energy of the gas for several strokes.
The heater is decoupled from the cooler and generates the hot gas on demand - and can be recharged with heat for a short time, regardless of a changed work cycle.
The single-stroke hot gas engine has two circuits, a cold and a hot circuit. The operating gas can work under high pressure in this closed circuit without the sealing problems that are known from rolling diaphragms.

If necessary, heating can also be done with solid fuels, e.g. charcoal.

The heat only generates work in the fully heat-insulated expansion space. The hot gas expands over a variable expansion section, as can be seen on the <270° expansion engine>. After that it is exhausted. The gases are cooled down in the cooler and create a vacuum at the rear of the rotary piston. Compressed as a cold gas under high pressure, it is fed to the heater heat exchanger and a vacuum is generated on the back of the piston, which increases the working stroke.
The work cycle can begin again.

Astonishingly, the conventional Stirling engine is more efficient than the Otto engine, but it never really caught on. It's not just the complicated mechanics and the size of the motor, it's also the rather slow heat transfer that is tied to the RPM.
At this point, the single-stroke hot-gas engine is intended to improve efficiency by allowing the speed to be increased without having to limit the rate of heat transfer over time. For these reasons, the heater can be made extremely large and act as a reservoir.

For a mobile engine, the hot gas is generated by a relatively small burner with recuperative heating of the combustion air. See <Burner> and the <Protocol>.

The conventional four Stirling cycles are shown below as a scheme cycle 1 - 4 Of course, Stirling engines are also built with two cylinders, it's the same principle.

A change occurs when the heat obtained from the external heating can be converted into work more effectively according to the single-ended principle. The Stirling advantages are used in this way, the disadvantages are remedied or do not appear.
One of the advantages is that the single-stroke hot-gas engine works according to the <single-stroke principle>, but the conventional Stirling engine, as the cycle sequence shows, works as a four-stroke engine from 1 - 4.

stirdia 2.jpg (7171 bytes) picture

The diagram shows the ideal Stirling process, which looks very similar to the Otto four-stroke process. Here, too, it is apparently not possible to make the four bars disappear.
In the P -V diagram is
from 2 to 3 isochoric heat input > and 4 to 1 isochoric heat removal

The conversion of heat into work takes place here in a compression space and an expansion space - in between there is a heat exchanger, the so-called "regenerator".
At this point, a lot of thermal energy is lost because, paradoxically, heat must be supplied during the compression process. (But not cold fuel as in the single-stroke engine).

The four processes in the Stirling engine sequence, as shown below, are reduced to one process by the single-stroke system, similar to the single-stroke engine, the four strokes are reduced to one stroke.
Load > Work.

The conventional Stirling process as a reminder

bar 1

Expansion room Regenerator Compression room
takt1st.jpg (3082 bytes) picture
1 - 2 of isothermal compression
The picture shows the isothermal compression of the air or the working gas, which may be under constant system pressure. This cycle of isothermal compression takes place between 1 and 2 in accordance with the cyclic process.

bar 2

Expansion space, regenerator, compression space cycle 2st.jpg (3709 bytes) picture
2 - 3 of isothermal heating

Analogously to the single-stroke hot-air engine, it corresponds to charging through the heater heat exchanger via the non-return valves into the heat-insulated work area.

bar 3

takt3st.jpg (3740 bytes) picture
3 - 4 of isothermal expansion

This expansion corresponds to the stroke or the expansion sinon in the hot-air single-stroke engine

bar 4

takt4stl.jpg (3372 bytes) picture
4 - 1 isochoric cooling

Corresponds to the exhaust in the closed hot-air single-stroke engine, in the large-dimensioned cooler heat exchanger.
This simple scheme of the conventional Stirling engine shown above can also be imagined as a 5-zone engine. From left to right, are in a common cylinder (simplified)

Zone 1 compression space > Zone 2 cooler > Zone 3 regenerator > Zone 4 heater > Zone 5 expansion space.

The heater 4 > transfers the heat (amount of heat), if necessary through the displacer into the regeneragate 3 > the compressor 1 pushes the "cold" air or gas through the regenerator, the air is compressed and heated and is pushed into the expansion space 5, expands and does work.
It is a relatively complicated thermodynamic process, which also creates a need for an explanation of the "hot-gas single-stroke engine". As a hot gas engine that makes it easier. This is because the single-ended principle means that there is no need for a regenerator. Does the difference between <regenerator> and heat exchanger remain to be clarified?

In comparison is more accurate if you use the expansion steam engine for comparison with the single-stroke hot gas engine.

Already during the design of the single-stroke system, it was worked out that this single-stroke process is suitable for making the slow-running Stirling engine fast-running by means of a single-stroke hot-gas engine with two heat exchangers.

Portions of heat are not shifted, but kept ready on demand in a "storage heat exchanger" at a high temperature of up to 1000°C - and then loaded.

This results in another advantage: The REKU burner heats the combustion air so that, in the most favorable case, the burner exhaust gases can reach the dew point limit.

The heat transfer times are very short,

The special feature of the hot-gas single-stroke engine is that the processes take place simultaneously, without difficulties in heat transfer occurring.
Performance and efficiency are favorable compared to a petrol engine without a heat generator because a high level of compression is saved.
The base pressure (gas) in the closed circuit of the hot-air single-stroke engine can be maintained continuously with little energy, if necessary using a small compressor.
No amounts of heat have to be shifted from "cold" to "warm" and cooled because the usual exchange from cold to warm takes place outside of the actual cycle time in large heat exchangers, in this case the cooler. In this way, the delay caused by the warm-cold shift is bypassed.
According to the diagram below, the single-stroke engine becomes a high-speed hot-air engine, the wish of many engineers and inventors.
The external combustion - the closed circuit for charged compressed air or another heat transfer gas remains as usual.
The usual rolling membranes can be dispensed with. Only a single shaft leaves the motor housing and has to be sealed.

The schematic drawing deviates from the practical structure, because the cold air and hot gas paths are kept as short as possible in the practical structure.
Cooler and heater well thermally insulated so that the cooler and heater cannot influence each other.

The "single-stroke" - Stirling sequence (the hot-gas single-stroke sequence) < The new type of Stirling engine >



stirling1.jpg (23291 bytes) Image

:

Blue is the compressor side with cooler, red is the fully thermally insulated working side with heater

The cooler and heater can be accommodated between the compressor block and the working block to save space, or they can be arranged separately outside the engine.

Transferring the advantages of the single-stroke engine to the hot-gas engine saves complicated, expensive sealing elements. The hot air charging and expansion take place very quickly, so that small slip gaps are sufficient for tightness.

The addition of micro-fine metal powder or graphite to the system gas circuit can then ensure tight rotary elements instead of burn-off.

The design based on the V - A - V motor can be expedient, possibly also more advantageous with the two-shaft motor

The recommended hollow structure, so-called sheet metal design, can have pitch diameters of 1000 mm and more when using low temperatures.

The peripheral speed is intended to be 6 m/s on the pitch circle.

konvor 4.jpg (13270 bytes) picture
Image


(1) axles, (2) vane hub, (8) the vane

No high-quality, highly heat-resistant steel sheets are required for low temperatures.

See: <Parts>

The schematic drawing shows the simplified circuit.
Except for the cooler, the entire engine plus heater is fully thermally insulated

The cold The hot
circular purchase circular

stirl5.jpg (20855 bytes) picture

The warm circuit is full - possibly separated from the cold circuit by a vacuum.

The one-shot shown here
Heat exchanger or regenerator ?
The "hot gas - single-stroke engine" expands the constructive scope for Stirling engines. This new type of single-stroke Stirling engine is fast-running thanks to its single-stroke design and therefore does not require a regenerator. Instead, two normal high-performance heat exchangers are used.
Heat exchanger #1 as a heater
Heat exchanger No.2 as a cooler If the cooler in the heating circuit, the motor is used as a combined heat and power plant to heat the building.
Due to the special feature of the single-ended principle and the omission of the regenerator, the question of the difference between heat exchanger and regenerator repeatedly arose in the discussion. One could not shake off the notion that the regenerator is practically "only" a heat exchanger, which is only partly true.

On the other hand, the definition should be corrected: The regenerator is a heat accumulator that flows through easily, but not a heat exchanger that stores the heat until the cold gases from the compressor are pressed through the regenerator and absorb the previously stored heat. It is only at this moment, in the second cycle, that the regenerator becomes a heat exchanger. This hot gas then expands in the expansion space.

With the single-stroke principle, the compressor pushes the hot gases directly into the expansion chamber of the rotary vane cylinder via the heater, which also has the properties of a heat accumulator. The process runs in one direction, the optimally expanded hot gases, which have a variable expansion distance, puff out in a closed circuit and are fed to the cooler.
In addition, the negative pressure created by the cooling acts on the other side of the rotary vane and increases the rotary force.

The single-stroke hot gas engine has a simple structure, so that the engine can work under a high system pressure of up to 200 bar, which only has to be charged once. This is the prerequisite for a small, compact engine design, provided the heat exchangers, heater and cooler, are matched to this high system pressure.

Depending on the arrangement of the heat exchangers, the motor housing has only one structurally problematic opening to the outside, the seal of the motor shaft.
All other transitions of the heat accumulator can be accommodated in the absolutely gas-tight housing.

Rolling diaphragms and other seals in the motor are no longer required!

*System pressure is the unmodified air or helium pressure present in the circuit.
The air pressure can be kept constant with a small compressor, helium with a pressure bottle.

Because of the very long expansion distance, the single-blade, single-stroke engine is particularly suitable as a hot-gas engine. See < The single-bladed single-stroke engine> (two-shaft engine)

See also: < Stirling engine and burner >

burner1.jpg (38356 bytes)
Image



<Excerpt from the test report < Click

The burner achieved a firing efficiency of 97.4% at an exhaust gas temperature of 74°C and was well insulated with the exception of the supply connections using glass wool. The heat generated was dissipated by cooling water.

The drawing shows the design of the burner. Fanned porous silicon carbide discs led or generated a temperature close to 1500°C (incandescence). The distance to the heated medium was 6mm. 3mm for the heat zone 3mm for the burner tube wall thickness.
All those involved in this test found it interesting that, despite visible glowing embers (white heat) through the exhaust pipe, the exhaust gas temperature was only 74 °C.

The thought arose as to why it shouldn't be possible to extract work directly from such a device instead of heat.
Tests have shown that if environmental conditions are created in an engine cylinder that are similar to the conditions in the recuperative burner tube, it can be successful.

Also see in connection <The steam engine> which can be built in a closed circuit as a 1-stroke engine, if necessary more effectively and smaller than the hot gas engine. The steam engine is not only tied to steam.

The advantages of the single-stroke hot gas engine:

(1) Compression and expansion occur simultaneously. There is no leading or lagging.

(2) The working gas is not bound to helium, but unsaturated water vapor, a vapor-air mixture or another heat-resistant gas can be used if necessary.

(3) There is only one critical sealing point, the shaft exit from the motor housing.
Everything can be kept absolutely tight in the burner. (No rolling membranes, etc.)

(4) Dry lubrication is provided. with graphite, Teflon, talc or another proven metal-based dry lubricant, e.g. These lubricants are provided in powder form which, as suspended particles, also take over the piston seal.

(5) The working gas manages with low pressures. A working pressure of more than 100 bar does not have to be sealed, but a very high heating temperature of the working gas may suffice with 20 to 50 bar.

(6) There is no crankcase, so there are no sealing problems either

(7) Direct heat charging allows the speed to be increased largely as desired.

(8) <Self-sealing> and self-healing of the rotating elements also applies to the single-stroke hot gas engine.


(9) The efficiency can be doubled and the motor is downsized.
airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Re: Impulse Radial Stirling Turbine

Post by airpower »

Would be nice to get hold of the original CD
https://web.archive.org/web/20170312033 ... fr000.html
Compilation of frequently asked questions

Question 26
According to your statements, the single-stroke engine can also be used as a new type of Stirling engine, especially since the Stirling engine is an engine with external combustion. How is there an advantage over the conventional Stirling engine, especially since the efficiency of this machine is already particularly good today?

Answer : The advantage lies in the fast running, because the working gas volume is not, as usual, shifted between a cold and a hot room and supplied with hot air or hot gas via a <regenerator>. The hot gas is kept ready on demand. Therefore, fast continuous strokes are made possible (high speed). The self-contained inching process is similar. If the temperature is supplied from the outside, this gas temperature may be low or high. Then only the engine size changes with the power. High temperature - small motor, - low temperature large motor.
This is double-walled in every incineration plant and can be integrated into such a single-stroke hot-air circuit. This means that the efficiency of the system can also be used at low temperatures.

This also applies to the return of e.g. Any waste heat can then be used cheaply via the hot-gas single-stroke engine.

The compressed cold gas or air coming from the cooler is warmed up or heated in a heat exchanger shortly before charging, charged according to the single-stroke principle, expanded and exhausted back into the closed circuit. The cooled heat transfer gas is then fed to the compressor and the process is repeated. The usual recuperator is omitted, which raises <*** Question 186> about the difference between heat exchanger and recuperator. If you want to achieve acceptable performance at relatively low temperatures, the rotary piston surfaces and locking rollers must be enlarged. Both can be designed as a hollow sheet metal construction. This design option also belongs to the development reserves of the single-ended system.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


*** Question 186

https://web.archive.org/web/20151130080 ... /a186.html

Heat exchanger or regenerator ? <hot gas engine>

The "hot gas single-stroke engine" type HL - A - HL expands the constructive scope for Stirling engines. This new type of single-stroke Stirling engine does not require a regenerator. As a result, the hot air does not have to be absorbed in the regenerator, after which the heat is released again. This expenditure of time is saved, so that the engine speed can be increased. and Instead, two normal powerful heat exchangers are used.


Heat exchanger No.1 as a heater (is a large-area heat absorbing heat exchanger) that has storage properties and can store a multiple of the amount of heat required per stroke. This simplifies the control of the external heating and makes the engine more responsive.
Heat exchanger No. 2 as a cooler is designed in a normal heat exchanger design with a large area and high performance and can, if necessary, cool the air or gases down to the dew point limit - before they are fed to the heater.

stirl 1.jpg (23291 bytes)

Due to this special feature of the single-ended principle, the regenerator is not used in the usual way, but works continuously.
The definition regenerator was helpful in the discussion, that practically the heater performs a combined function, heat exchanger and at the same time heat accumulator.

The definition should be corrected: The regenerator is a heat accumulator that flows through without great resistance, but at this point it is not yet a heat exchanger that stores the heat until the cold gases from the compressor are pressed through the regenerator and absorb the previously stored heat. It is only at this point that the regenerator becomes a heat exchanger in the second cycle. This hot gas then expands in the expansion space and does work.

With the single-stroke principle, the compressor pushes the hot gases directly into the expansion chamber of the rotary vane cylinder via the heater, which can also have the properties of a heat accumulator. The process runs in one direction, the optimally expanded hot gases puff out in a closed circuit and are fed to the cooler.
In addition, the negative pressure created by the cooling acts on the other side of the rotary vane and increases the rotary force.
The hot and also the cold circuit is secured by non-return valves in the direction of flow.

The single-stroke hot gas engine has a simple design so that the engine can work under high system pressure*, up to 200 bar if necessary, which is the prerequisite for a small, compact engine design, provided the heat exchangers, heater and cooler, are matched to this high system pressure.

Depending on the arrangement of the heat exchangers, the motor housing has only one structurally problematic opening to the outside, it is the motor shaft seal.
All other transitions of the heat accumulator can be accommodated in the absolutely gas-tight housing.
*System pressure is the unaltered air or helium pressure present in the circuit.

The air pressure can be kept constant with a small compressor, helium with a pressure bottle.

Because of the very long expansion distance, the single-blade, single-stroke engine is particularly suitable as a hot-gas engine. See < The single-bladed single-stroke engine>
The closed circuit shown in the hot gas engine is also valid for the steam engine in connection with the single-bladed single-stroke engine. <steam engine>


stirl5.jpg (20855 bytes)


Regenerator = 1/2 heater 1/2 accumulator in one body


3<Menu> <Directory> <Register>
airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Re: Impulse Radial Stirling Turbine

Post by airpower »

https://web.archive.org/web/20150629191 ... /a143.html

143

The steam engine (fully suitable for automobiles!)

Making the steam engine suitable for use in automobiles still occupies many an engine designer and inventor today.
One of the oldest mechanical engineering disciplines is still waiting - to become suitable for automobiles.
One has to ask why is this so? One hopes from the fact that the steam engine, the only known "single-stroke engine", could make the breakthrough to leave the Otto four-stroke principle in order to improve the degree of efficiency.
The chances are good, because the steam engine is a single-stroke engine, can be built with thermal insulation and can be operated with a closed circuit. The steam can be generated with a high-performance burner with recuperative air preheating. So far, this has not been possible with petrol or diesel engines.

The constructive solution seems to be relatively simple, because the expansion steam engine has been known for a long time. The long strokes and motor size were - and continue to be - the obstacle.
The connection boiler > machine is manageable - and the advantage of the steam engine as a motor is well known. An engine that can be built fully thermally insulated, together with a <momentum steam generator>, would also possibly come to a real - unadulterated 60% efficiency if boiler and engine efficiency are multiplied.
The single-stroke hot gas engine would be in competition, as is the <high-speed Stirling engine>.

When the efficiency of the steam boiler and the machine multiply in the closed circuit, there are automatically advantages that were missing in previous concepts. The steam engine then becomes a fast-running engine that is operated with superheated high- or low-pressure steam in the closed. <The first idea about it>

The single-stroke steam engine type D-A-D is an expansion steam engine, a single-stroke machine without dead centers with an extremely long expansion path.
The same laws as for the single-stroke engine therefore apply to the single-stroke steam engine.
Since it is related to the single-stroke engine, good thermal insulation, four to eight steam strokes with variable expansion per revolution, and an absolutely closed circuit between the heater and cooler can be implemented.

The inclusion of the single-stroke steam engine in this discussion came from the belief that the single-stroke principle represented the long-awaited solution for a closed-cycle steam engine.

If <thin-wall design> and thermal insulation are adopted from the single-stroke motor, the rotary bodies are designed as hollow bodies, as in the case of the thermally insulated single-stroke motor. Rotary pistons, locking rollers and cylinders take on the temperature of the superheated steam and then work very effectively without significant heat losses, i.e. the smallest portions of superheated steam are converted into work very effectively thanks to the possibility of expansion. That weakens the arguments against the insufficient amount of vapor.

The counter-arguments are in the direction of the amount of steam based on an output of up to 40 kW.
Since there is no combustion in the steam engine, which is important for the continuous sealing of the rotary piston, appropriate emulsions are added to the steam. For example, graphite, micro-metal powder (nickel or chromium) which, with or without high-temperature plastic binders such as Teflon or silicone, provide the sealing as suspended particles, but not, as is assumed - for which the lubrication is responsible. In the steam engine, the rotary bodies are guided by gears and are positively controlled without contact and run towards one another without lubrication.

*The emulsions are kept in suspension in the cooler by ultrasound or mechanically in vortex chambers. Due to the closed steam system, the suspended matter cannot escape, but rather seals the entire engine system.
This single-stroke steam engine has the advantage over the fast-running <single-stroke hot gas engine> that isothermal compression is omitted and in this case the steam engine also becomes a high-speed engine based on the single-stroke principle.
This makes the D-A-D steam engine fully suitable for use in automobiles.

>> These tests are running worldwide, so far only the single-stroke engine was missing !! >>
A single-stroke steam engine is a risk-free entry because of the relatively low temperatures from 200°C and as a superheated steam engine with a maximum of up to 400°C, with a high-pressure steam boiler or as a momentary steam generator with recuperative combustion air.
It is to be expected that there will be counterarguments because of the expected increased formation of nitrogen oxides with this technology, which is expected as a result of the <recuperative> combustion. This does not apply if the combustion process is designed according to the <recu burner>. < Burner test report >
With wood or wood gas firing, an interesting source of energy for renewable energy sources would be developed, and therefore to improve the living environmental conditions in underdeveloped countries will be an ideal solution.

The recuperative burner with recuperative combustion air preheating is suitable as a steam generator, but other commercially available solid fuel heat generators should also be considered.
External combustion engines such as the Stirling engine require an efficient heat source.
the steam engine an efficient instantaneous steam generation.
The REKU burner shown, with an efficiency of over 97.4%, can also be supplied via the external compressed air, which analogously shows the problems if this method is to be transferred to an internal combustion engine.
As can be seen from the <Test report> for the REKU burner below, an efficiency of 97.4% is achieved with a test load of 7.4 kW.

nbrenner.jpg (17921 bytes)images
Image

The schematic drawing below shows the single-stroke engine with external combustion air supply as an <energy store>

without a fuel connection (yellow), the engine can also be used as a steam engine according to the diagram.
The compressed air connection becomes the superheated steam connection, the exhaust gas is fed to the closed circuit or the external cooler.
picture
The fuel connection can be closed circuit in steam operation
be converted as a lubricant supply for the gears.

dad4.jpg (32786 bytes)
Image
External compressed air or steam!

This single-stroke steam engine has the advantage over the fast-running single-stroke hot-gas engine that isothermal compression is not required and in this case the steam engine based on the single-stroke principle becomes a high-speed engine.
With this technology of the single-stroke process, which has not been used up to now, the steam engine is fully suitable for use in automobiles. It is an application that previously failed due to the limitation of the speed of a reciprocating steam engine - and did not allow such high performance.

>> These tests are running worldwide, only the principle of the single-stroke engine was missing !! >>

The two-shaft single-stroke engine with an extremely long expansion section, the <single-blade 270° engine> is particularly well suited.
airpower
Posts: 91
Joined: Tue Oct 05, 2021 5:56 am

Re: Impulse Radial Stirling Turbine

Post by airpower »

https://web.archive.org/web/20151121071 ... /a025.html
<Menu> <Directory> <Register>

025

High-performance burner with recuperative combustion air preheating.

External combustion engines such as the steam engine or the Stirling engine require an efficient heat source. The highly heated water vapor as an energy supplier is known from the steam engine. Less well known is hot air or hot gas as an energy supplier.
The well-known methods are the Benson boiler for steam generation and other aggregates
The instantaneous gas generation, which usually works with a relatively high degree of efficiency, only works effectively with air preheating. See: <067>
Since the combustion air preheating accelerates a combustion process, but on the other hand provides less combustion oxygen, this must be taken into account accordingly.
The fully thermally insulated single-stroke motor works according to this principle. Therefore, the adjustment begins with a very favorable speed range of 1000 to 1500 rpm.
If you get into a higher power range, not only the power but also the efficiency can be increased according to the single-ended strategy.
In single-stroke engines, this is achieved by recuperative fresh air or mixture preheating. The
Combustion portions become smaller, the <Explosive Combustion> faster and the RPM can
increase.
The combustion principle in a REKU-operated burner refers to the combustion in the engine cylinder
transferred reveals the associated problems. Transferred to the internal combustion engine
the same conditions would have to be created as in the burner.
In the burner, glowing silicon carbide disks support the rapid combustion reaction
Efficiency of 97.4% is achieved.
If similar amounts of heat generated, not for heating purposes, but very effectively in the smallest of spaces
in the engine cylinder, unlimited upwards in temperature can be generated, then there is also the
Possibility to take this heat as work.
In this case you are well on the way to a fully heat-insulated single-stroke engine.
It is interesting - in any case, the - < test report > that shows how the solution with a heat-insulated
engine could look like.
The question about that? <Question 24>
picture

burner1.jpg (38356 bytes)
Image



Fresh air at 20° C. is supplied at the air inlet connection 2 via a relatively small blower with approx. 40 mbar and flows via the recuperator 5 via the antechamber, substantially heated into the mixing chamber 4 which is filled with metal mesh. The fuel gas (propane) is fed into the mixing chamber via 1, mixed and ignited at the nozzles and burned on the periphery of the ceramic discs.

The exhaust gases then flow through the inner exhaust pipe 8 into the recuperator, heat up the combustion air and the process can begin again.

The realization matured that it must be possible to generate heat (i.e. pressure) at over 1000°C by means of an explosion using the smallest quantities of mixture in the smallest space. With an exhaust gas temperature of only 74 °C. with recuperative mixture or preheating of the previously compressed combustion air, it makes sense to take work instead of heat. You just have to manage to distribute the heat generated here over small portions and burn it individually and several times within the four-stroke time.
With this thought, the question arose as to the difference between explosion and explosive combustion, because explosions are undesirable in engine combustion.

This is one of the essential basic ideas that led to the single-stroke engine.

To the thermally insulated engine with <charge air heating> < please click!

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067

Efficiency data according to textbook tables for information


Steam boiler 0.80 x single-stroke motor with only 0.60 means 48% efficiency instead of 28%. That would be a huge win in itself. Conceivable also with fuel gasification. See: <The car steam engine>
Type D-A D

The general information is very important, because it easily eludes the assessment!

Benson boiler 90.00 - 92.00
Fuel gasification 70.00 - 75.00
Steam boiler 70.00 - 85.00

Further table values of the efficiencies for orientation:

% Locomotive 15.00 - 25.00
Large gas engine 24.00 - 26.00
Steam engines ............10.00 - 28.00
Steam turbine 19.00 - 25.00

Constant pressure turbine 28.00 - 30.00
Gasoline engine .... 24.00 - 28.00 at 10% load the specified values drop by approx. 50%
Diesel engine 35.00 - 38.00

Centrifugal compressor 70.00 - 75.00
Capsule pump 85.00

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T23

Excerpt from the test report (Gas Heat Institute ESSEN)

Run-up line Company: Type: Submersible torch Ba: 1020
Date: 02/18/1982 Nozzle: 6 x 0.4 tg: 19
Pressure regulator Gas type: Propane Hu : 25.81 kWh/m3 j : 0

Red. factor: 1.00 Wo 22.52 fan air

h h test load CO2 CO O2 connection nozzle pressure flue gas room
f w kcal/h kW vol% vol% pressure mbar 15° C mbar °C temp. °C

97.4 7500 8.7 11.5 >0.2 3.0 62.5 5.5 78 19
97.4 6400 7.4 10.8 0.08 4.2 41.5 4.0 74 19
93.4 17200 20.0 11.7 0.2 2.1 280.0 24.0 150 13

This result of a recuperatively operated immersion gas burner, which, mind you, achieved an efficiency of 97.4% in the smallest of spaces - and that at an exhaust gas temperature of only 74°C - showed that under similar conditions work can also be done instead of heat.

See: <The heat-insulated single-stroke motor>

See: <high-speed single-stroke Stirling engine>

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101

Explosive combustion and explosion ? - ! The difference !

An explosion is rapid combustion, and explosive combustion is also rapid explosion.
The conclusion that an explosion is an explosion leads to the understandable question of the difference?
<long and short stroke?> and <blank cartridge principle - buffering>

A four-stroke explosion is understood to mean the explosion of large, highly compressed quantities of mixture, which tend to deflagrate as explosions at top dead center, especially when the engine is not working - and are dissipated as heat via the cooling system. This lost pressure is known as tapping.

An explosion combustion, on the other hand, is a buffered explosion - an unchecked explosion - of the smallest mixture quantities with subsequent expansion, i.e. a high work output that results in a sudden pressure drop.
In the case of explosive combustion, work is released immediately by a primary explosion in the direction of rotation.
Explosive combustion releases all the heat in fractions of a second. The increase in pressure cannot cause knocking, the pressure only increases in the direction of rotation.
The work done by increasing the pressure results from the difference between the piston speed and the speed of the explosion. Even under load, the explosion pressure drops abruptly to piston speed before it is exhausted.
At this point, the heat or pressure loss is significant, a low residual pressure is sufficient for exhaust, which contributes to the high efficiency, because the exhaust gas temperature is very low due to the variable expansion section.

(High internal engine cooling through expansion!)

In the case of fuel-air mixtures that are to be used technically, the different explosion limits must be taken into account. For example, the explosion limits for petrol vapor are around 2.5% in the lower range and around 5% in the upper range.
Hydrogen, on the other hand, is around 4% in the lower range and around 74% in the upper range. Using hydrogen in the lower range or at the upper limit is problematic because the explosion limits are between 4% and 74%. A fully thermally insulated single-stroke engine operated at 800°C would therefore be the ideal hydrogen engine. Such an engine allows all conceivable mixtures of hydrogen with other gases, which is to optimize the hydrogen resistance of the materials used.
Atmospheric explosions that take place within these limits develop variable explosion speeds, i.e. in the upper (rich) range the explosions become slower, and when they drop below the lowest ignition limit, there is often no reaction.

The pressures generated generally do not exceed 15 to max. 20 bar. In engine combustion, the explosion or combustion pressure is added to the compression pressure. The main reason why compression is used is that ignition is also reliable in the middle range.
On the other hand, a fixed mixture volume does not have a quantum more oxygen left over for combustion than the uncompressed mixture. Low pressures at the point of ignition can be compensated by high combustion chamber temperatures

Atmospheric explosions that take place within these limits develop variable explosion speeds, i.e. in the upper (rich) range they become slower, when they drop below the lowest ignition limit there is no reaction.
The pressures generated generally do not exceed 15 to max. 20 bar.
In engine combustion, the explosion or combustion pressure is added to the compression pressure. It is therefore compressed so that ignition is also reliable in the middle range.
The compression work must first be applied by the engine and becomes visible when calculating back from the mean pressure.
An example is the diesel engine with a high initial pressure - compression plus ignition plus explosion (combustion) are around 50 bar, the mean pressure is 8 bar.

Every fuel-air mixture, whether lean or rich, whether atmospheric, whether low or high compression, would like to explode or burn according to its characteristics. A rapid combustion, - an explosion reaches velocities up to 500 m/s causing the knocking
With an average piston speed of 6m/s, a combustion speed of 20 to 30 m/s is sufficient. In the thermally insulated single-stroke engine, it is also possible to convert explosion velocities of 500m/s into technically usable pressure and expand it variably.
This is done by buffering according to the <blank cartridge principle>, in which the buffer energy is used a little later, but efficiently.
What remains after an explosive single-stroke combustion is a residual flash heat from the expansion. <Explosion without knocking !>
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When converting small amounts of heat (pressure pulses) into work, the small amounts of heat must be generated by the highest possible temperatures. The more precisely this is maintained, the better the efficiency.
These very small portions of the mixture are each loaded from two sides into the glowing segmented cylinder at supersonic speed, homogenize - explode - expand and spread over eight to sixteen strokes within two revolutions.

The time for one stroke is half a revolution, regardless of whether it is the same for a four- or single-stroke engine. ·
If a four-stroke mixture portion is divided into eight or sixteen small single-stroke portions, the explosive combustion in the unchanged four-stroke time (= 2 revolutions) means that you have indirect
achieves a · <combustion time extension> with the same performance. <small amounts of mixture>

The explosion after the turning point is tantamount to retard ignition, but does not shorten the combustion time.
Whether with 2 bar or 5 bar, whether it was charged at low or high speed,
the expansion distance automatically adapts to the conditions of the explosion. *

*Maximum expansion distance is fixed after full load.
This means that at half full load only half the expansion distance is required.
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