Research On The Heat Transfer Characteristics Of Hencken Burner

In the field of combustion temperature measurement,Hencken burner is often used to calibrate the laser temperature measurement device.To some extent,the flame quality of the Hencken burner determines the accuracy of the laser spectral temperature measurement device.At present,it is generally assumed that the flame generated by the Hencken burner is stable and uniform,and the temperature and composition of the flame are equal to the flame equilibrium temperature and composition.In fact,the heat transfer between the Hencken burner and the external environment will cause the flame temperature to deviate from the equilibrium value,which leads to the decrease of the laser spectral temperature measurement precision.Therefore,the research on the heat transfer characteristics of the Hencken burner is very important for the calibration of the laser spectral temperature measurement device.Through the experimental measurenent and numerical calculation of Hz and CH4 flame,the heat transfer characteristics of the flame of the Hencken burner are studied.The flame generated by the Hencken burner is mainly composed of the heat radiation of the high temperature gas,the convection heat loss of the high temperature gas and the convection,and the heat loss of the flame and the wall surface of the combustor.The vast majority of the heat transferred from the flame to the wall of the burner is passed to the flow of gas,which is used to increase the temperature of the current and the energy can be recovered.Only the heat loss from the surface of the burner can be considered as heat loss.Under the condition of the same heat loss,the larger the flow rate,the lower the temperature.Under the condition of the same heat loss,the larger the flow rate,the lower the temperature.The experimental results show that under the condition of plane flame,the flow rate of H2:flame can be very large,so the temperature decrease caused by the heat loss is small,and the temperature is close to the equilibrium temperature.However,in order to maintain the flat flame;the flow rate of the CH4 flame must be very small,and the heat loss caused by the heat loss is more serious.Premixed combustion of Hencken burner by premixed fuel and air,compared with the diffusion flame,premixed combustion can slightly improve CH4/air flow rate,and slightly lower temperature drop,the flame temperature close to the equilibrium tremperature.In order to isolate the effects of ambient air on the flame,the Hencken burner is also accompanied by N2.Increasing the N2 flow will,of course,enhance the isolation effect,but also increase the convective heat loss,reduce the flame temperature.Therefore,there exists an optimized N2 flow,which can isolate the air and reduce the flame temperature.In this paper,the optimal flow rate of NZ with H2 and CH4 under different working conditions is studied by experiments and calculations.Based on the analysis of the heat loss of the Hencken burner,the optimal setting of Hencken combustion for temperature and component calibration is given at the end of the paper.The optimal setting includes how to realize the maximum flow rate,how to determine the temperature core area affected by the convection heat transfer,how to consider the gas radiation in the core area,and the calculation method of the main component concentration.