Rippled Displacer to Decrease Hot Dead Space

Discussion on Stirling or "hot air" engines (all types)
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Rippled Displacer to Decrease Hot Dead Space

Post by blade » Fri Mar 07, 2014 11:34 pm

All dead space reduces the thermodynamic efficiency of a stirling engine. However, hot dead space is required for the heater tubes in order to allow for a thermodynamically efficient transfer of heat into the working gas.

Instead of using heater tubes, is it possible to use a displacer which looks like the following.

| | | | | | | Imagine the displacer obtained as the solid of
__________ revolution when this shape is revolved around its center.
(Note: the vertical lines should extend all the way down.)

Using a displacer such as the one described above provides much more surface area to heat a gas, but it also removes the dead space created by heater tubes.

Assuming the added surface area is the same as that obtained through the use of heater tubes, is there any problem with such a displacer?

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