Experimental And Simulation Study On Liquid Fuel Combustion In Porous Media Burner

The parking heater is an auxiliary heating device used when the vehicle stops,which can improve the comfort of the personnel.At present,the combustion devices of parking heaters on the market use mechanical atomization to achieve the crushing,evaporation,mixing and combustion of liquid fuel with air,but mechanical atomization is prone to problems such as insufficient mixing of liquid fuel and oxidant and incomplete combustion.In this paper,the evaporation porous medium combustion structure of liquid fuel is proposed.The effects of different evaporation structure,burner structurc paraneters,fuel consumption and excess air coefficient on combustion characteristics are studied.The main research work is as follows:An evaporation porous medium combustion experiment platform for liquid fuel is designed and built.The influence of two evaporator structures on the combustion characteristics is studied.It is found that the temperature of the convex evaporator is significantly higher than that of the circular cake evaporator.The temperature is the main factor affecting the NOx emission,and the residence time of the reactants in the high temperature region is the decisive factor affecting the CO emission.A porous media burner with conical tail is designed,which significantly reduces the emissions of NOx and CO pollutants.CO decreases with the increase of altitude,while NOx emissions first decrease and then increase with the increase of altitude.The cold start characteristics of conical porous media burners at different altitudes are studied.It is found that when the altitude is less than 1700m,the NOx emission first increases sharply and thenslowly increases as the combustion progresses.When the altitude is greater than 1700m,the NOx emission first increases and then decreases as the combustion progresses.A combustion chamber structure with ceramic foam in the liquid fuel porous medium burner is proposed.It is found that ceramic foam can effectively increase the combustion intensity in the burner and reduce CO emissions.The NOx emission decreases first and then increases with the increase of the distance between the foam ceramic and the evaporator.The combustion characteristics of four kinds of foam ceramic composite structures are experimentally studied,namely "Zheng Baotao","Fan Baotao","Zhong shape" and "Gong shape".It is found that the pollutant emission of "Fan Baotao" foam ceramic structure is the lowest.A three-dimensional mathematical and physical model of liquid fuel porous medium evaporation combustion is established.The high temperature zone of combustion decreases with the increase of excess air coefficient,and increases with the increase of fuel consumption.Compared with the cylindrical porous medium burner,the flame length of the conical porous medium burner is significantly increased.The combustion high temperature zone gradually decreases with the increase of excess air coefficient,while the combustion high temperature zone increases with fuel consumption.