Research On The Performance Of Waste Heat Recovery Device Of Automobile Tail Gas With Spiral Coil

In order to improve fuel efficiency and reduce automobile exhaust pollution to the environment,this article in view of some 12 m traditional buses with constant curvature car tail gas waste heat recovery heat exchanger,spiral coil pipe by experiment and numerical simulation method,the study of the heat transfer performance,and based on this,advances a new type of efficient variable curvature spiral coil heat exchanger.In the process of experiment,by changing the water temperature of circulating water,circulating water flow,the engine exhaust temperature,engine exhaust flow,environment temperature,these a few parameters,study the influence on waste heat recycled,the results show that change the circulating water temperature,waste heat recovery heat and heat recovery are increased with the increase of water temperature and lower,within the scope of the study,circulating water temperature of 40 ?,waste heat recovery heat and heat recovery is the largest;Change the engine exhaust temperature,waste heat recovery heat and heat recovery are increased with the increase of exhaust temperature increased,within the scope of the study,the engine exhaust temperature is 350 ?,waste heat recovery heat and heat recovery is the largest;When the circulating water supply is changed,the heat recovery and heat recovery rate of waste heat increase with the increase of circulating water supply.Within the research scope,when the circulating water supply is 3.6m /h,the heat recovery and heat recovery rate of waste heat are the highest.When the exhaust volume of the engine is changed,the heat of waste heat recovery will increase with the increase of the exhaust volume of the engine,and the recovery rate of waste heat will decrease with the increase of the exhaust volume of the engine.Within the research scope,when the exhaust volume of the engine is 123 m /h,the recovery rate of waste heat is the maximum,and when the exhaust volume of the engine is 223 m /h,the recovery rate of waste heat is the maximum.Change the environment temperature,waste heat recovery heat and waste heat recovery rate increase with the increase of the ambient temperature,within the scope of the study,when the environment temperature is 10 ?,waste heat recovery heat and heat recovery is the largest.The models of fixed curvature spiral coil heat exchanger and variable curvature spiral coilheat exchanger were established by numerical simulation.In the range of Reynolds number from4000 to 14000,the influence of two geometrical parameters of coil diameter and spiral diameter on the resistance and heat transfer performance of a fixed curvature spiral coil heat exchanger is studied.It is found that changing the coil diameter has little effect on the flow resistance of the heat exchanger,and the heat transfer increases with the increase of the coil diameter.When the diameter of helix is 70 mm,the increment of flow resistance is the largest,and the heat transfer increases with the decrease of helix diameter.The air outside the fixed curvature spiral coil tube is not enough contact with the coil tube,so the heat exchange efficiency is low.In the range of Reynolds number from 4000 to 14000,the influence of two geometrical parameters of winding number and cone Angle on the resistance and heat transfer performance of variable curvature spiral coil heat exchanger is analyzed.The results show that with the same length of the spiral coil,the convection heat transfer ability of the outer side of the tube can be effectively improved with the increase of the conical Angle,and the increase of the resistance.The recovery of tail gas waste heat of different variable curvature spiral coil heat exchanger is higher than that of fixed curvature spiral coil heat exchanger by 18.8%.In 15° taper Angle,the comprehensive factor optimal variable curvature of the spiral plate heat exchanger.In this paper,the method of experiment and numerical simulation provides a theoretical basis for the optimization of spiral coil.