Abstract
Heat transfer during compression and expansion of gas is investigated to obtain a correlation that is easy to use in the design of the reciprocating energy conversion machines. We carried out experiments to measure the heat transfer characteristics to̸from gas during compression and expansion to obtain the correlation. These measurements were performed using a piston-cylinder assembly over a range of volume ratios, frequencies, mean pressures, gases, and internal extended surface areas. The heat transfer was estimated thermodynamically from experimental pressure-volume data. Dimensionless groups for heat transfer are discussed in order to correlate the data. The product of the dimensionless heat transfer and specific heat ratio was found to be optimal and was correlated with only the Peclet number for a wide range of conditions, even for gases having different specific heat ratios. The temperature amplitude of the center of the test space was obtained, and it is found that the penetration depth reached the center when the Peclet number is in the range from 20 to 30.
