Numerical Simulation Of The Marine Air-conditioning Heat Exchanger Based On The New Ladder Type Spiral Baffle

In order to select a heat exchanger of the air conditioning system to adapt to the weather conditions of different sea areas.To enable ships to work in extreme environments.The geometrical structure,internal flow and heat transfer process of heat exchanger are extremely complex.And it is one of the first technical measures to study the internal flow and heat transfer process of heat exchanger by numerical simulation.This thesis studied the shell heat exchanger.Numerical simulation was carried out by convection heat transfer between the ambient temperature and the deep sea water.We got the velocity distribution,temperature distribution and pressure distribution of the whole heat exchanger.The simulation results were analyzed and compared.And we proposed the optimization scheme of the structural parameters of the baffle plate in the heat exchanger.This paper studies the shell heat exchanger.Numerical modeling the ambient temperature heat transfer with deep sea water.The velocity,temperature and pressure distribution of the whole heat exchanger are obtained,and the simulation results are analyzed and compared.The optimum proposal of the structural parameters of the baffle plate in the heat exchanger is proposed.This thesis uses AutoCAD platform.To create the three-dimensional physical model of the single bow baffle and the ladder type baffle plate shell and tube heat exchanger.Through Gambit software,the three-dimensional model of shell heat exchanger was divided into meshes.Fluent fluid analysis software was used to solve the heat exchanger model.To explore the effect of single bow baffle plate layout and the size of spiral baffle plate.To compare the effects of two different types of baffle plate on heat transfer.And select the ladder type baffle plate heat exchanger with characteristics of good heat exchanging effect for further optimization.The main points of this study are as follows.According to the cooling and heating condition of ship air conditioning systems.Under the same external dimensions of the heat exchanger.First,simulate the shell side flow of single bow baffle heat exchanger with 100 mm,150mm,200 mm,250mm and 300 mm length of A and 200 mm,143mm and 111 mm baffle spacing.Third,simulate the shell side flow of ladder type baffle with 86 mm,64.5 mm and 64.5 mm length of a,and compare with the single bow baffle heat exchanger with the same baffle spacing.The influence of different baffle plates on heat transfer is discussed.Last but not least,select the ladder type baffle plate heat exchanger with characteristics of good heat exchanging effect for further optimization.After thesimulation of the heat exchange,the influence of the optimized baffle plate on heat transfer was discussed.The results show that the ladder type baffle heat exchanger proposed under all sea water source heat pump air conditioning system.The fluid flow in the heat exchanger is closer to the spiral flow.Local resistance losses are reduced.The effective heat exchange area of the heat exchanger is increased.Then the heat exchange is enhanced.What's more,the ladder type baffle heat exchanger improve the leakage flow problem of spiral baffle.At the same time,the pressure drop is only about 32% of the single bow baffle heat exchanger.The comprehensive performance is better.Furthermore,the comprehensive performance of the double ladder type baffle heat exchanger has been further improved.