Study On Unsteady Heat Transfer Characteristics Of Gun And Rocket Charge

A gun or a rocket launcher is an apparatus projecting gun rounds or rocket rounds. Accurate strike is emphasized in modern war, so the artillery forces have to endeavour to raise shot accuracy of guns and rockets. Charge temperature is an important parameter influencing firing distance of a gun or a rocket and its measuring result greatly affects the firing accuracy of weapons. It is a pity, but, that presently domestic artillery forces still use way of 20 year ago, which is already approved to be greatly defective, to measure charge temperatures in reasonable regulation and with backward equipments. So at present, charge temperature measuring in the artillery is not precise and the dissatisfactory actuality urgently need to be changed. Under the background, a systemic research about how to accurately measure or obtain the real-time temperatures of gun chare or rocket charge in the battlefield is mdae, and main research contents in the dissertation are shown below:(1) In order to provide data to the experimental and theoretical studies on unsteady heat transfer characteristics of charge, experiments measuring thermophysical properties of several kinds of domestically produced powders are done. In addition, the experiments are of use to studies on powders' thermophysical properties;(2) The paper simulates several kinds of gun and rocket charges' typical woking conditions in battlefield and measures temperatures of a few points in them. After it is indicated that there exist four types of errors if charge temperatures measured in the traditional way, and definitions of each kind of error and overall error are given, by settling and analyzing the experiment data, the paper gets value of each temperature measuring error in every experiment where the traditional measuring way is used. In this way, the paper researches defects of the traditional charge temperatures measuring way;(3) When the military checks a newly developed charge temperature measuring device, temperature change rate of surroundings of the charge is required to be greater than a certain value. So the author uses an attemperator to perform temperature-lift experiments on several typical gun charges and rocket charges, and in the expeiments measures temperatures in different time of a few tested points. The experiment data can be used as a criterion to check the theorical calculation or newly developed charge temperature measuring devices;(4) According to different structures peculiarities and heat transfer mechanisms that different charges have, the paper divides total charges' heat transfer problems into two types and establishes corresponding mathematical and physical models for them;(5) The unsteady flow and temperature field of a rocket charge including only a propellant column is calculated, corresponding to temperature-lift experiment of the charge in an attemperator. The calculation results are in agreement with the actual test ones in the experiment. On basis of the above calculation, the paper analyzes flow and temperature field characteristics of the charge and studies influence on the charge temperature field exerted by convection in the annuli and radiation among solid walls;(6) Refering to the related documents, the author derives method and steps to simulate the unsteady temperature field of a complicated charge with unstructured grids and SIMPLE algorithm. The above derived method is carried on to unsteady temperature field calculation of two complicated rocket charges. Temperatures of all tested points gotten by calculation are close to those gotten by experiment. Based on the calculations, a research on the flow and temperature field characteristics of one of the aforesaid charges has been done;(7) After construction of cell vertex grid scheme or cell centered grid scheme, unstable temperature fields of two different gun charges are simulated. Heat transfer boundary conditions of the two problems belong to the third type and the author calculates such problems with iterative method. On base of temperature field simulation, the field characteristics of one charge are analyzed;(8) Plans measuring charge temperature in two different methods are discussed. Being in charge of developing heat transfer similar model of a rocket charge, the author has devised one which meets the temperature measuring need.