The Research On Velocity Distribution In The Environment Simulation Laboratory

In this dissertation,the internal field of a laboratory of desert environment simulation was studied and analyzed.The numerical simulation method and physical experiment method was used to investigate the internal flow field of the laboratory.First,according to the sizes of the axial-fans and the laboratory,the numerical models of the fans and the laboratory were built with CAD and GAMBIT.The numerical simulation was carried out with commercial CFD software-Fluent and theκ-εmodel was established to research this project.In order to more accurately describe the velocity field of the test area,the grids which are in the model experiment region below solar simulator were made more compact.In addition,the variation effect of the height of the solar simulator and the opening with exhaust hood on the flow field was also investigated.And the demand of different velocity outlet conditions could be met by changing fan rotational speed.Then,the characteristic section was selected in the laboratory to acquire the distribution of velocity field.Finally,The results of experiment were compared with the ones of the simulation.From the results of the simulation and the experiment,it is shown that the method of numerical simulation coupling fan and laboratory model was feasible to the simulation of the laboratory.When the pressure in fans' inlets was 72.3Pa,the results of the simulation agree with the experiment ones.According to the rotational speed of the fans which was at the range of 100-300 rpm,the lengths of the non-uniform areas caused by the supply fan stator were at the range of 986-1023mm,and the lengths of the areas which were influenced by the return fan were at the range of 542-583mm.It was found that the air distinction below the model experiment region was negligible no mater the height of the solar simulator was 2m or 1.5m.When the exhaust fan was turned on,the fluid flow deflected upward less than 300mm beneath the solar simulator,and the influence on the flow field of the model experiment region can be neglected.As the influence of the air condition in fans' outlets,the distribution of the velocity in the front of the model experiment region was not uniform.However,model experiment region was not influenced.And the uniformity of the model experiment region in the laboratory could be improved by installing the contraction at the outlets of the blowers and fixing the honeycomb mesh at the tail of the contraction.