The Heat Transfer Numerical Research Of Fluid-solid Coupling Of Gasoline Engine Cooling Pump-water Jacket And Cylinder Block- Head

The cooling system with good heat dissipation has an important impact on engine’s dynamic and reliability. In order to find out the details in cooling process, flow problems in cooling jacket have become an important research project. To learn more about the thermal property of the cooling system further, this paper will focus on the research of solid-liquid coupling heat transfer of cooling pump-water jacket and cylinder block- head combining with the radiator.This paper takes 166 QML single-cylinder water-cooled engine as the research object. To have a fluid-solid coupling simulation on the cooling pump(which been changed on the dorsal nose area)-water jacket model and cylinder block-head in the Fluent using the design flow value as boundary condition, and then analyzing the distribution of water flow fields and engine’s surface temperature. The results showed that: this type of water jacket’s points hole can meet the cooling requirement of the engine basically, and the improved water jacket model has decreased the combustion chamber wall temperature.Independently studying the cooling water jacket is not well enough to understand the entire cooling system’s matching issue and cooling capacity, so to add a cooling water pump to the original model to cooling water pump models constitute a fluid-solid coupling model of water pump-jacket and cylinder block-head. The next is to choose an appropriate calculating model MRF for the pump in the paper after comparing the dynamic characteristics of pump under the mathematical model MRF and slip grid area in that the mathematical model of pump has a great impact on the flow fields of pump while others did not have a depth research of that yet. And launching on a matching calculation between the pump- water jacket model and the radiator model to obtain the accurate pressure boundary condition of the coupled model in this cooling system, the results been applied on the fluid-solid coupling model and then the calculating results shown that: the error between the calculated flow value and the design one is only 2.5%that means the design flow is reasonable, the average temperature difference of inlet and outlet is closer to the experimental one, that the error is reduced to 5% that means the radiator model matched the pump-water jacket model very well in this cooling system.To further explore the thermal performance of the cooling system. The thermal energy of the cylinder head increased by 10% and increasing power of the radiatormoderately that is to increase two pieces of radiator heat sink under the condition of the pump power unchanged. The new pressure boundary condition can be obtained by matching the radiator model enlarged and pump- water jacket model. The analysis of the simulation result that obtained by fluid-structure coupling model for the cylinder head cooling capacity increased by 10% under the pressure boundary showed that cylinder head wall temperature is raised significantly and circumferential cylinder wall temperature has exceeded the upper limit, at the same time, the maximum temperature in the water jacket cooling liquid has reached boiling threshold. Thus, the performance improvement of cooling system in the cylinder head is less than 10% and further measure is to improve the pump power.