Technical Paper
Calculation of Heat Flux Integral Length Scales from Spatially-Resolved Surface Temperature Measurements in an Engine
1991-02-01
910721
Instantaneous heat flux rates were measured in a spark ignited CFR engine. A new heat flux probe was used which had seven thin film platinum resistance thermometers, spaced 1 mm apart, on a Macor substrate. Instantaneous heat flux was measured at each sensor location and the integral length scale of heat flux was calculated from the spatial cross correlation data. A swirl flow condition was generated by use of a shrouded intake valve, and tumble flow was created by rotating the shrouded valve 90°. An unshrouded valve gave a more quiescent flow condition. Under motoring conditions, peak heat flux was 70% higher for swirl flow conditions than quiescent flow conditions, and the total heat rejected during the closed portion of the cycle was 50% higher with the swirl flow than the quiescent flow. The peak heat flux for swirl flow compared to tumble flow was 30% higher and the total heat rejection was 10% greater.