| Due to the bad climate situation and the sharp differences in temperature of plateau,it is more difficult for the people and engineering machinery working than on the plain.With the development of the western region,various kinds of construction projects emerges throughout the western region,and the requirements of the ability to bear the bad plateau climate of engineering machinery is higher and higher.Thus,it is vital for the air conditioning on the construction of machinery cab on the plateau,to reasonable adjusting air temperature,velocity,pressure and other factors to make the indoor air flow comfortable for people.In this paper,the author chose the loader's cab as the research object,through the analysis of three different working conditions of temperature field,velocity field and pressure field,which contains plain?plateau and plateau of increasing pressure,using numerical simulation method,to explore the air conditioning airflow organization regular of the cab air-conditioning on the plateau.First of all,in this paper,the author introduced the research status at home and abroad about the cab flow field,and the research contents and methods are described briefly.After that,the author introduced the use of computational fluid mechanics basic theory knowledge,including computational fluid control equation,theory and numerical simulation calculation turbulence model,and introduced various kinds of double-equation the turbulence model the types of wall function and it's advantages and disadvantages in detail.This paper selected the normal k-? double-equation model and the standard wall function method.Then,made calculation and assumptions to the cab fluid,and simplified the model of the loader's actual bridge,used the Pro/E build the loader,s3D model and the human body boundary model,and used the Workbench divide the grid.The relationship between atmospheric density,atmospheric temperature and altitude was described in this paper.Set up three kinds of working conditions of the plateau,plateau of increasing pressure,and the plain.Used the Fluent sets the conditions for the cab boundary,chose the inlet of mass flow,and carried out the value simulate computation for three kinds of working conditions.Then to set up the different test plans and test points by using the CFD-post that is back processing software,and to analysis the comparative results of simulations of the temperature field?velocity field and pressure field on the test plans and test points in the flow field of the cab.The last set up evaluation system of the cab flow field and simply introduced the evaluation of the purpose and meaning and commonly used air distribution evaluation index,according to the index,analysis of comfort of human body.This research reveals,under working in environment of low pressure and low density of plateau,the energy of air flow from air conditioning of cabin declines faster,leading the temperature and the speed of the air supply decreased,making the cab flow field's average temperature decreases and average speed is becoming slower and slower,while at the same time the fluid pressure is basically unchanged.Under the plateau of increasing pressure,the temperature and velocity of air flow of air conditioning in the cab are between the plain working condition and the plateau working condition.It explains that increasing pressure of cab could solve the problem of low pressure and low density in plateau for the cab flow field. |
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