Study On Temperature Field Of The Cylinder Liner For OPOC Diesel Engine

With the continuous development of engine technology and the increasingly serious energy and environment problems, the OPOC(Opposed Piston Opposed Cylinder Engine) has been widely concerned with the advantages of small volume, low fuel consumption, low emissions, light weight and high power density. However, high power density must be accompanied by high thermal load. Therefore the thermal load of cylinder liner, cylinder head as well as piston in OPOC engine has been closely watched. In this paper, the research on flow and temperature field of water jacket and cylinder liner of the diesel engine is conducted through the experiment and numerical simulation method.Firstly, in the present work, research was focused on the PIV test of the fluid flow in a water jacket. The three-dimensional structure of water jacket was extracted from the machine and accordingly simplified. The model was processed by quartz glass and acrylic. PIV test bench has been set up in order to measure the velocity field of three measuring points in five water flow rates, meanwhile, simulation of the flow field was carried out based on FLUENT software. The experimental results and calculated results of three measurement point have been analyzed to get the suitable solution model for calculation. Then the model was applied to the flow field calculation of actual engine water jacket, thus providing water-side boundary conditions for temperature field calculation.Then the investigation on temperature of the engine cylinder has been conducted by test and numerical analysis. During the research process on temperature of the engine cylinder liner, the thermocouple temperature measurement method was adopted for 5 measuring points when the power density is 30 kW /L. And numerical simulation method was employed to calculate the temperature field by considering the cylinder liner and its contact between high temperature gas and heat transfer of cooling water. In the numerical calculations, gas boundary conditions were obtained from the result of thermodynamic cycle calculations acquired by GT-SUITE software. Water-side boundary conditions were acquired by the fluid-solid coupling calculation of cylinder liner and the cooling water jacket by ABAQUS and FLUENT software, in which the boiling heat transfer was taken into consideration. The simulation results were in good agreement with the experimental results with maximum error of 6.3%, indicating that the coupling calculation of temperature field distribution of cylinder liner and cooling water jacket is of relatively high reliability.Finally, the developing engine cylinder liner with 60 kW/L power density was also simulated by the calibrated simulation model of liner heat transfer. Based on the numerical results of temperature field, an improvement method was proposed.