Study On The Method Of Measuring The Heat Flux Of The Explosive Field

The damage element of the target in the combat department explosion field mainly includes fragments,shock wave overpressure,asphyxiation effect and thermal effect,etc.With the research of the large equivalent combat department and fuel air combat department deepening,the thermal damage effect of the explosive field is more obvious,it's measured mainly by the heat flux density.So,it is of great significance to study the method of measuring the heat flux of the explosive field.According to the requirements of explosion thermal damage test,and combined with the advantages and disadvantages of different test methods and the current research status of heat flux density sensors,this paper presents the design of a new type of an infrared contact heat flux density sensor.Based on AUTODYN software,the blast temperature field of the airborne explosion of 40.966 kg TNT was simulated,and a preliminary assessment of the thermal damage in the explosion field was conducted,thus the requirements for the design of the heat flux test system are determined.The overall design of heat flux density test system is given,and according to the one-dimensional steady state heat transfer theory,the principle of measuring the heat flux of the test system is given,the relationship between the heat flux measured by the sensor and the temperature change rate of the rear wall of the heat-sensitive element is obtained by it.Subsequently,the specific structure design and material selection of the components of the heat flux density sensor(thermal element,blackbody coating,optical system;,photoelectric conversion element,sensor shell,etc.)were carried out.Based on the ANSYS finite element simulation software,the blackbody coating material and thermosensitive element have been thermodynamically simulated to discuss the influence of the black body coating on the heat transfer of the thermosensitive element.The results show that blackbody coating only slightly reduces the output amplitude of the sensor and has no effect on the overall structural design of the sensor.Thereafter,according to the output characteristics of the sensor signal,the design of signal conditioning circuit for heat flux sensor is completed.Through the design of amplifier circuit,the filter circuit and the transmission circuit,the output voltage signal of the photoelectric component of the sensor is transformed to voltage signal output of 0-5V.Finally,an absolute calibration method which takes the blackbody furnace as the standard radiation source is used to calibrate the sensitivity of the designed heat flow sensor,and the response sensitivity of the sensor is obtained,and its linearity error is 5.91%,which meets the sensor's design requirements.An explosion temperature field test of a temperature and pressure bomb of 100kg is carried out on the heat flux sensor,results show that the heat flux density of the explosion field is up to 9.35MW/m2,and the feasibility of using the designed heat flux density test system to test the explosion field is verified.