| After going through SARS, our country realizes the current situation with backward level of biosafety laboratory, increase the input into this respect, build one rank high, function complete biosafety laboratory.biosafety laboratory is a means to realize the security of living beings while operating the pathogenic microorganism of higher danger class, the purpose is not polluted for protecting personnel, products and environment,etc., it not merely depends on the clean technology of air or some sterilized apparatus, comprehensive building construction, warm and coherent giving drain off water, electric apparatus, craft all professional, of various fields hardware of technology, and software measures such as the laboratory operational procedure,etc. but the comprehensive safe security system of forming. According to biological extent of injury of target laboratory deal with, divide the biosafety laboratory into four grades, or moderate breeze security of living beings what laboratory deal with to can cause people or animal serious disease, easy cause of disease body that travel directly or indirectly among individual. The cause of disease body suspend among the atmosphere in the form of aerosol, its diameter is very little, it is extremely apt to slip into the deep department of the respiratory system, so have very great threats to experiment personnel. General security of biosafety laboratory consist of first class protective screen and second protective screen prevent the poisonous external ease of cause of disease, the first class protective screen means that there are biosafety cabinet, centrifuge,etc. to close the apparatus on the inside of the main laboratory. Among them, biosafety cabinet use for in operate have infective experiment material, preventing biological pollution to personnel and a kind of apparatus of danger of experiment. Its operation principle is to protect staff members and experiment articles and avoid the infringement of the medium-sized and highly dangerous material through one-way laminar flow and high-efficient way that filter. Second protective screen refers to facilities such as the periphery of the laboratory and ventilation pipes,etc..Biosafety car can be regarded as the small-scale biosafety laboratory, the function that it has laboratory of higher grade of biosafety laboratory and also has a flexible, economical and practical characteristic. At present, only France develops the car of tertiary security of living beings in the world, it is formed after the container trunk has been transformed, it is 12.09 meters long, 2.9 meters high, 2.45 meters wide. Divided into three major parts of room, buffer ,main laboratories, technic room in the car .It has reasonable air organize, come, " lock ", live in harmful gas that laboratory act as measure, producing allow their other eases to produce outdoors with " design of ladder " of atmospheric pressure, from buffer room to decrease progressively gradually by key atmospheric pressure of laboratory, key atmospheric pressure - 60 Pa of laboratory. What is called air current organization, mean confirm handing over (the Hui nationality) draught form, position, specification, quantity and handing over wind amount to (the Hui nationality) suitable, and blow parameter,etc.. And particulate matter that indoor pollution sources send out will produce different sport under air current function of sport, there are different purification results to also enable the main laboratory. Confirm main laboratory reasonable air current organize, become, design and develop security of living beings important link of car just, it is the groundwork of this thesis.As to how choose air current organizational form rationally, how appraise air current quality to organize result, CFD method to study air power knowledge question effective and economic method in the air conditioner. CFD is the abbreviation of English Computational Fluid Dynamics (calculate hydrokinetics). It is development with the development of computer technology, number value computing technology. To be simple, CFD does the " fictitious " experiment on the computer, for the flow situation of the artificial and real fluid of simulation. Basic principle its whether number value ask, solve differential equation that fluid flow, obtain whom fluid flow field dispersed distribution at continuous area, thus similar to the fluid situation of flowing of simulation.Key gas of laboratory flow state turbulance flow state, research key air current of laboratory it organizes to be to take exercises research of going on to indoor turbulance. At present, mainly there are three kinds of number value methods to adopt to the turbulance: Direct numerical simulation, the method based on Reynolds average Navier-Stokes equation and large whirlpool simulation method. Direct numerical simulation to ask N-S equation to solve transient state directly, considered to be reliable turbulance simulation method most at number value emulation. But because its work load is very large, it is very difficult to employ on the existing computer. Can not flow field employ analyze, in main laboratory. Large whirlpool method of simulation to come, imitate large whirlpool of yardstick directly with N-S equation of transient state, small whirlpool impact on large whirlpool to come, consider through approximate model. Expecting still very much to computer memory and pace of this kind of method. Two kinds of methods described above are both simulation methods not yet ripe and complete.The method based on Reynolds average Navier-Stokes equation is based on Reynolds average movement equation and pulsating movement equation, depend on theory and combination of experience, introduce a series of model suppose, set up one group describe turbulance average quantity close theory computing technology of equation group. It can divide into based on that Boussinesq suppose whirlpool viscous mode and based on that Reynolds stress transports the equation two steps square and high-order square close the mode on the whole. The former can regard subdividing as and mix the length, an equation and two equation modes. Have pros and cons with various turbulance model simulation indoor all air flow, standard equation to count, put forward to high Reynold, claim too high Reynold counts the equation model. But flow and prop up in the adjoint viscidity of cliff side in storey in the field actually, the turbulance Re is counted very low, the method have limitation to area these, so project prop up layer adopt the function law of cliff side in viscidity often, still adopt high Reynold to count the equation model to imitate in the turbulance core. Flow field adopt low Reynod count equation model can very fine simulation flow field entirely, but needed by it computer memory heavy, machine too long, have the terms as general project person at present. New zero equation model can better reflection room complicated turbulance flow and form simple calculating time little, but remain to study and prove in its adaptability. So, this thesis adopts the standard equation to combine the function law of cliff side to imitate. Ask, solve leaning towards differential equation for now impossible non-linear directly, so must turn differential equation the can change, take the place of, ask the algebraic equation solved through some method, differential equation that this is dispersed. Algebraic equation that receive approximate to differential equation. Among them, according to different methods, has adopted different assumptions, the different number value solution of forming the same question of directing against. As to heating, ventilating and air-conditioning low-speed, can't press, flow and conduct heat question of field, adopt the limited volume law to carry on dispersedly. On this basis, ask to solve SIMPLE algorithm. Through organize, imitate to key four dynamic air current of operating mode of laboratory designed thesis, analyze, give draught number, rows of draught number, security of living beings location of cupboard to main laboratory influence result that air current organize separately, thus choose the optimum scheme. One of scheme consist of one hand over draught, the indoor air can not be distributed evenly, there is a vortex greater in intensity in many places. Scheme two increase one give draught, air current organize have heavy improvement, quantity and intensity of vortex reduce too, the area that the pollutant density spread has been reduced too. Through compare two scheme corresponding to examine density value a bit obtain scheme two air current, organize, superior to one scheme too. Three scheme whether more than assign one rows of draught, analyze velocity field and density field it obtain, want, reduce indoor pollutant density invalid by increasing and arranging the outlet. The fourth scheme is the position that has changed the cupboard of security of living beings and arranged the draught, through an analysis of its velocity field and field of density, it is the most ideal to obtain this kind of scheme. On this basis, the pace is that the blowing amount has been imitated to blowing differently, obtain increase in pace, indoor pollutant density corresponding reduction too, but the increase of corresponding wind speed of the working range, this does not accord with the demands for laboratory of security of living beings, so recommend the rational fetching value range 0.45m/s-0.55m/s. It is security of living beings key laboratory of car that give draught and arrange design and to assign, have sure directive significance rationally indoor apparatus of draught.
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