Researches On Rapid-Firing Gun Barrel Cooling Method

During the process of rapid fire artillery firing, the gun barrel subjected to hightemperature and high pressure coupling shock loads, as the shooting number increased,reduced the mechanical strength of the barrel. When the reduced mechanical strength closesto the yield limit of material, the shooting should be stopped to cool the barrel. In view of thegun barrel subjected to high temperature and high pressure coupling shock loads by propellantgas when firing，the gun barrel transient thermal response was analyzed in the natural coolingand vaporization cooling method，with different rules of firing. As well as testing thetemperature of gun barrel under the vaporization cooling method. The main contents andconclusions of present study could be showed as follows:(1) Taking heat transfer theory and other knowledge as the foundation, established themathematical model of heat transfer in gun barrel.(2) When natural cooling by using finite element method，numerical simulation of heattransfer in gun barrel under different firing mode were carried on，the transient thermalresponse of barrel was acquired. By the analysis of the simulation results，the gun barreltemperature field changing rules were obtained. The numerical simulation indicated thatunder the different fire mode the rules of temperature changes of barrel are different; duringthe shooting process the cooling method has no effect on the barrel temperature, the outerwall temperature of the tube depends largely on the number of projectiles, the finaltemperature is a result which the projectile number and the cooling time affect together;Natural cooling efficiency is not enough, the natural cooling method could meet the coolingrequirement of firing at a small number, but the cooling requirements of long-time continuousshooting will not be able to meet. The other cooling methods to enhance heat dissipationwould be needed.（3）The tube’s transient thermal response was calculated when using the vaporization cooling method， and the different cooling effectiveness between natural cooling andvaporization cooling method to gun barrel temperature field was also studied. Throughcontrast analysis found that the larger fire number was，the more significant cooling effect togun barrel when using vaporization cooling method.(4) With the combination of boiling and phase change heat transfer theory and relateddata, the heat storage of gun barrel in the firing process was calculated by mathematicalmethod. And the continuous fire number of rapid fire artillery was estimated when the coolantin the cooling jacket was vaporized completely.(5) By establishing a reasonable temperature testing program, the temperature field ofrapid fire gun barrel with vaporization cooling method was tested experimentally. Throughexperimental tests the temperature curves of the outer wall of the barrel was obtained. And thetest result indicated the method of vaporization cooling could cool the gun barrel whilecontinuous firing，keep the temperature of the outer wall of the barrel below maximumtemperature for reliable work，which was300℃. What’s more，the experiment result showedthat when the cooling jacket water injection was about80%，it can meet the barrel coolingrequirement for all ammunition.