| Influence laws which different gas concentration functing in gas explosion in piping have been studied by experiment research, theory analysis and numerical simulation.Gas explosion flame and shock wave propagation experiment under different concentration is carried on in the experiment piping of 700 millimeters diameter. And the analysis of the test data is as following:①Influence of concentration impacting on peak pressure is analyzed. And peak pressure has a cubic function with propagation distance with same test point distance.②Influence of concentration impacting on flame propagation velocity is analyzed. And flame propagation velocity reciprocal has a cubic function with propagation distance with same test point distance.③Flame propagation velocity is small in explosion source nearby, then rises to some peak value and weakens gradually.Based on the experimental data, the paper formulates the principle of promulgation deflagration in shock wave changing to detonation from gas explosion in the gas explosion flame propagation and shock wave. Influence of concentration impacting on peak pressure is analyzed. Under different gas concentration, the gas -air mixture is on the different oxygen balance condition, which causes the chemical reaction advancement changing, and flame temperature, explosion pressure, pressure rise rate and so on have been influenced also.Using flow simulation platform and on the base of gas explosion propagation theoretical model, the gas explosion propagation numerical simulation is carried on applying the continuous phase. Through analysis and comparison of simulation and experimental results, something is found.①Maximum pressure of explosion source is not the maximum pressure of whole process.②Shock wave maximum pressure value decreases in explosion source nearby, then rises to some peak value and weakens gradually.③Maximum pressure value decay process is not monotonous, and has fluctuations.④Some differences exist between experiment value and simulation value, and majority of simulation value is larger than experiment value, which is influenced by Wall surface condition hypothesis.⑤Simulation value reduces in exporting nearby. And the tendency is opposite to experiment one.
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