A Critical Comparison of Hot-Wire Anemometry and Laser Doppler Velocimetry for I. C. Engine Applications

Hot-wire anemometer and laser Doppler velocimeter measurements have been taken in a motored reciprocating engine and compared to assess the validity of hot-wire measurements. The procedure used to account for the sensitivity of the hot wire to changes in the gas temperature is extensively investigated. The results presented show that for the optimum conditions of known flow direction, low turbulence level, and low compression ratio, the hot-wire anemometer can provide useful mean velocity results. Accurate hot-wire turbulence intensity measurements appear to be possible only for the intake and exhaust strokes.