The Optimization Of Natural Cooling Waterways In S195Diesel Engine

The cooling medium’s three-dimension flow in cooling system of single cylinder diesel engine directly influences the thermal load of high temperature components,the cooling efficiency,heat distribution and energy utilization of diesel engine,it concerned with power performance,fuel economy,reliability and durability of diesel engine,it is always the focus of diesel engine designer.Improving cooling system has become an important task to diesel engine design,and the numerical simulation is an important means to research the coolant flow and heat transfer in diesel engine water chamber and to optimize the structure of water chamber.This article which takes cooling waterways of S195diesel engine as the object for studying has carried on the theoretical analysis and simulation to the three-dimensional flow and heat transfer of cooling water.According to the two-dimensional blueprint of diesel engine,using the three-dimensional CAD software Pro/Engineer to establish the geometric model of diesel engine,and conduct the necessary simplification under the premise of ensure consistency as far as possible.The model is checked and meshed by the FLUENT pre process GAMBIT,subsequently,the model are computed and displayed,and then the results are post-processed and analyzed all by FLUENT. During simulation, assumes that Cylinder cover cylinder water and water cavity of the cooling fluid flow is steady,density is only related to temperature, they are just turbulent flow. The flow of the coolant is natural convection, driving force of the flow is the change of density and water vapor generation and movement o f bubbles,it can use polynomial to express the relationship between temperature and density, heat transfer in the cooling water to use boiling model determined by vc++programming.From the simulation computation results nephogram, the natural cooling of diesel engine cooling water cavity design is reasonable, basically achieved the cooling design requirements, but there are still some places in need of improvement。Such as cooling water cavity flow rate is too small; particularly cylinder head bridge of the nose area flow dead zone; from the cylinder block water cavity flow to the water flow through the cylinder head water less; coefficient of thermal conductivity bridge of the nose area is too small do not meet the requirements。Thus cooling channel design principle based on the geometric model of the prototype partial improvement of the new scheme is proposed and numerical simulation, by comparing the solutions before and after the improvement of flow field, identify strengths and weaknesses, found that the improved model is more perfect, more meet the cooling requirements。...