Heat transfer during piston compression

An experimental and theoretical study has been carried out to determine the unsteady heat transfer from a nonreacting gas to the end wall of a channel during the piston compression of a single stroke. A thin platinum film resistance thermometer records the surface temperature of the wall during the compression. A conduction analysis in the wall, subject to the measured surface temperature variation, then yields the unsteady heat flux. A separate analysis based on the solution of the laminar boundary layer equations in the gas provides an independent determination of the heat flux. The two results are shown to be in good agreement. This is true for measurements that were made in air and in argon. Results for the heat transfer coefficient as a function of time are also presented and exhibit a nonmonotonic variation.