An Experimental Investigation of Liquid Coolant Heat Transfer in a Diesel Engine

An experiment which simulates operating conditions in a diesel engine cylinder head which are favorable for initiation of nucleate boiling is described and the relationship between heat flux and coolant passage wall temperature is presented. Measurements of temperatures in the head between the flame face and the coolant passages indicated nucleate boiling may initiate within the valve bridge at a wall temperature of approximately 393 K; however, forced convection was the dominant mode of heat transfer. The results compare favorably with J. C. Chen's heat transfer correlation which accounts for forced convection and nucleate boiling.