Study Of The Inhomogeneity Of The Cooling System For A V-type8-cyliner Diesel Engine

For multi-cylinder diesel engine, because of the number of the cylinders, the flow resistance andthe heat transfer, there will be uneven of water flux within cylinders. This will affect the engine’s coolingefficiency, heat load, heat distribution and energy utilization of the engine. This paper takes the coolingsystem of a V-type8-cylinder diesel engine as the research object and uses CFD analysis software Fluentto carry out the simulation research on uneven of water flux within cyliners. Mainly carry out thefollowing works:(1) The model of the cooling system is built by Solidworks. The grid model is built by ICEM, andfinally simulation calculation is conducted by Fluent. The water flux field, temperature field, pressurefield of the cooling system are analyzed by use of the post processing software CFD-post.(2) The flow rate and pressure drop of different oil radiator resistance is studied, and the resistancecoefficient of the oil radiator is determined.The influence law of oil radiator resistance on uneven ofwater flux within cylinders is studied. The conclusions show: oil radiator resistance coefficient can be setto4.5108. Under rated condition, When the oil radiator resistance coefficient increases from2108to6108, the water flux ratio between two row cylinders Q1/Q2increases linearly from1.205to1.437,theaverage water temperature difference between two row cylinders increases from0.4K to1.175K.(3) The influence of overall water flux on uneven of water flux within cylinders is studied and getthe following conclusions: water flux within1~4cylinders is more uneven than5~8cylinders. With theincrease of the overall flow, water flux within8cylinders tends to be uniform, but water flux within asingle row cylinders does not change significantly. Water temperature within5~8cylinders is moreinhomogeneous than1~4cylinders. With the increase of the overall flow, water temperature within8cylinders is more uniform, but water temperature within a single row cylinders does not changesignificantly.(4) The influence of temperature boundary conditions on the uneven of water temperature of eachcylinder is studied, including wall temperature conditions and oil radiator heat exchange. Get thefollowing conclusions: with the increase of wall temperature, outlet water temperature of1~4cylinderstends to be uneven, outlet water temperature of5~8cylinder also tends to be uneven, outlet temperatureof8cylinders tends to be uneven too.With oil radiator heat dissipation increases, uneven of outlettemperature of5~8cylinders decreases to some degree, but not obvious.