Simulation Of Flow Field And Local Resistance Of Road Way With Transect Mutation Based On PIV Experiment

With the rapid development of mine intelligent ventilation,the authenticity of mine ventilation network calculation is required to be higher,and the test results of ventilation parameters are required to be more accurate.The traditional local resistance test method can no longer meet the requirements of intelligent ventilation.The local resistance loss of the roadway is closely related to the wind flow field.In order to accurately measure the local resistance of the roadway,the boundary of the eddy current zone must be determined first.In this paper,based on the fluid under the premise of the similarity theory,the sudden enlargement design similar ratio of 1:20 roadway experiment model,smooth wind cannot reach fully turbulent flow within the experimental model,adopt the method of paste glass beads to increase surface roughness,the experimental model of wind can achieve full turbulence,but after the paste glass bead light penetration experiment model is poorer,PIV experiment cannot be carried out,so two models are made,one is smooth model for PIV experiment,and the other is roughness model for measuring local resistance.Using computational fluid dynamics(CFD)numerical simulation method,numerical simulation to the actual tunnel,found under the different roughness,into a complete turbulent critical wind speed of the wind,at the same time,according to the simulation results by eddy current area with the increase of wind speed increase before the same length,with the increase of roughness,eddy zone length decreases,smooth when eddy zone length of the longest,Therefore,the eddy current boundary measured by the smooth model can be used to drill holes on the rough model to measure local resistance.A sudden expansion experiment model with similarity ratio of 1:20 was built,and the flow field of the smooth experiment model was tested by particle image velocimetry(PIV)system.The rough model was drilled on the basis of the boundary position of the eddy current region measured by the smooth model,so as to ensure that the measuring point was closest to the boundary of the eddy current region but not in the eddy current region.The local resistance in the region was measured by pitot tube and multi-function parameter tester(TSI).At the sudden enlargement will drift shows that the results of simulations and experiments of the flow field testing,PIV test tunnel flow field,with the increase of wind speed,the sudden enlargement of roadway eddy zone length remain unchanged after first increases,the longest distance related to the roughness of vortex area,the greater the roughness,the shorter the eddy zone length,the same rule and the simulation results;In the local resistance measurement,the difference between the experimental results and the numerical simulation results is within 10%,which proves that the numerical simulation method of computational fluid dynamics can be used as a means to study the local resistance.On this basis,using numerical simulation method of computational fluid dynamics,the sudden contraction of roadway and sudden shrink tunnel flow field and local resistance are simulated,the simulation results show that the process to the sudden shrink tunnel vortex area length was associated with surface roughness and the ratio of the section before and after,the sudden enlargement roadway eddy zone length will increase with the increase of roughness,sudden enlargement ratio decreases;Two eddy currents will be generated before and after the sudden shrinkage roadway,and the length of eddy zone will decrease with the increase of the sudden expansion ratio and the increase of roughness.The local resistance and local resistance coefficient of outburst roadway increase with the increase of roughness and decrease of outburst ratio.The local resistance and local resistance coefficient of protruding roadway decrease with the increase of protruding ratio,and increase first and then decrease with the increase of roughness.It can be seen that the flow field and local resistance of the protruding roadway are more complex.The paper has 32 figures,8 tables,and 60 references.