Research For Heat Transfer And Spray Characteristics Of N-Heptane

The engine wall of Super burning ram engine is cooled by active cooling,the fuel in the engine is heated and sprayed into the combustion chamber of the engine by the nozzle and the analysis of high temperature fuel injection features helps guide the design of combustion chamber.In this paper,n-heptane is substituted for fuel oil and is based on the fixed pressure constant flow heat exchange and the variable pressure constant flow heat exchange test station and the change of heat coefficient and heat sink in two states were studied.Based on the particle image velocimetry(PIV)FLUENT software and computer numerical simulation technology,studies the macro after heating fuel injection characteristics and the characteristics of the micro jet.The study on heat and spray characteristics of the n-heptane mainly through the experiment method,designed and built constant pressure constant flow,variable pressure flow heat transfer test and high temperature n-heptane injection test bench.The heat exchange is used to study the heat transfer coefficient and thermal precipitation of the n-heptane.The high temperature n-heptane injection experiment is used to study the macroscopic injection characteristics of the n-heptane,including the Angle of the jet,the maximum width of the injection,the penetration of the jet,etc.FLUENT numerical simulation is used to study the microscopic characteristics of n-heptane injection,mainly includes: the particle residence time,particle radial location,particle radial velocity,axial velocity,particle diameter,particle distribution and the particle quality such as microscopic change rule.For the heat injection experiment of n-heptane,this paper takes the whole process of shooting from low temperature to high temperature under different pressure,and obtains a lot of information.The experimental results show that the heat transfer and high temperature injection characteristics of n-heptane are obtained.Through experimental research,found that in terms of heat exchange,in the process of temperature rise,the fuel heat sink a linear law of linear increase and the changing rule of the heat sink,there are no big changes.The reinforcement of convection heat transfer coefficient will gradually recover when the constant pressure is fixed.In the case of variable pressure constant flow,the reinforcement of convection heat transfer coefficient in the high temperature area will decrease gradually.In heating injection,found that the fluid temperature is important factors affecting jet macro morphology change,the increase of temperature the jet form has obvious changes,strengthen the jet atomization effect.Microscopic particles in the jet characteristics,with the increase of temperature,residence time of particles,the radial position and radial velocity,axial velocity,diameter,quality were altered obviously.