Experimental Study On Boiling Heat Transfer In Cylinder Head Cooling Channels Of Internal Combustion Engine

With the increase of internal combustion engine specific power, internal combustion engine has to face the problem of heat load in case of high power density. Therefore, the high-temperature cooling system appears in internal combustion engine. The core of high-temperature cooling is the use of the high heat transfer capability of boiling heat transfer, and the high-temperature cooling can reduce the temperature gradient of the internal combustion engine parts and improve its reliability. At the same time, it can also improve the economy, power and emissions of internal combustion engine. However, the boiling heat transfer in cylinder head cooling channels of internal combustion engine is more complex. In this paper, it makes use of a horizontal rectangular channel to simplify it, then to carry out the experimental study on boiling heat transfer in cylinder head cooling channels.In consideration of the temperature, pressure, flow rate of the test section inlet, the test bench of boiling heat transfer had been designed and built. The entire test bench is a closed circulatory system. It is mainly made up of the test section, medium circulation loop system, temperature control system, pressure control system and data acquisition system. The experiments of boiling heat transfer had been carried out. Then, the experimental data had been processed. It also indirectly calculates the heat flux, the wall temperature of the heating block top surface and the local heat transfer coefficient by means of the Fourier’s heat conduction law.Boiling heat transfer characteristics were studied. It mainly studied the influence of experimental factors on the local heat transfer coefficient and fitted the semi-empirical formula of local heat transfer coefficient. Through the study, increasing the super cooling of the medium and improving the flow velocity appropriately can play a role in the enhancement of boiling heat. However, increasing the pressure of the medium, the local heat transfer coefficient will be reduced. The semi-empirical formula of local heat transfer coefficient and the four factors of fluid velocity, pressure, temperature, and heat flux had been fitted and got. By comparison, the error between the calculated and experimental values is always less than15%. It can provide some basis to the design and application of boiling heat transfer mode in cylinder head cooling channels of internal combustion engine.