Experimental Measurement of Overall Heat Transfer Coefficient in the Automobile Radiator under Laminar Flow

Due to heat transfer importance in the automobile radiator (a type of compact heat exchanger) to optimize fuel consumption, overall heat transfer coefficient in the automobile radiator under laminar flow has been measured experimentally according to the conventional ɛ-NTU technique. In these experiments, water flow rate was varied in different levels (300, 400, 500 and 600 lit/h), water inlet temperature to the radiator has been changed (60, 70 and 80 ˚C) and the air speed for cooling of the hot water has been varied in different speeds (7.3, 9.2, 9.9 and 11.33 m/s) and the effects of these variables on the overall heat transfer coefficient (U) have been investigated. In the range of the study, maximum overall heat transfer coefficient is 66.5w/m2˚C, which is obtained at Reynolds numbers of 4224 and 2250 for air and water, respectively.