ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-431-1
ISBN Online: 978-1-56700-430-4
First Thermal and Fluids Engineering Summer Conference
INCREASING EXERGETIC EFFICIENCY THROUGH CONVECTIVE HEAT TRANSFER ENHANCEMENT IN A FINNED RECIPROCATING COMPRESSOR
摘要
Isothermal compression or expansion is one of the processes that needs heat transfer enhancement to have the
highest efficiency. First the convective heat transfer in the geometry of a special compressor, called "Finned
piston compressor" is considered: Laminar flow in concentric annuli's from the Nusselt number, entry length,
pressure drop and friction factor point of view are studied. The technique used in finned compressor is
exploitation of the full available heat transfer surface together with increasing heat transfer coefficient. Inducing a considerable mass flow by creating a pressure gradient between upper and lower chambers can circulate the air and increase the convective heat transfer. However this can produce a considerable viscous dissipation that can eliminate all the benefits of heat transfer enhancement. Besides, increased gap between the fins can increase the dead volume. The trade-off between these factors is studied in the current work. For each pressure gradient the best value of gap was found to maximize the exergetic efficiency. For the current geometry the initial pressure gradient is 1 kPa for which the optimized gap is 0.1 mm.