Optimal Thermal Control of Regenerative Heat Exchangers

Summary

The performance of regenerative heat exchangers with active control of the local heat transfer coefficient h or the local transfer surface area a is reported. It is found that within each regenerator pass (ha) should be enhanced in a narrow zone which shifts from the inlet face of the regenerator at the start of the regeneration period to the exit face at the end of the regeneration period. Outside this zone, (ha) may be small so as to limit the pressure drop of the fluid flow. When applying this control measure, the effectiveness of the regenerator approaches the counterflow exchanger effectiveness for rotational speeds which are only half of those conventionally used. Carryover losses and seal wear may thus be significantly reduced.