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Steady-State Simulation Of Minitype Air-conditioning Or Refrigeration System

Posted on:2006-09-09Degree:MasterType:Thesis
Country:ChinaCandidate:Z G YangFull Text:PDF
GTID:2132360155453241Subject:Thermal Engineering
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At present,refrigeration and air-condictioning manufacturefactory design products by traditional analogy ways on the whole.The effect is not perfect. Technique of computer simulation is infavor of reducing mistakes and enhancing characteristic formatching of components.On the base of balance of mass,energy,momentum, I bringforward means of Steady simulation. Characteristics ofrefrigeration system is described by Algebra equation and a littleone rank differential equation. Workload is less and veracity isgood.One-rank steam refrigeration system is researched in theory.In the condition of necessary hypothesis and predigestion,a kind ofclear ,simple ,stable arithmetic is adopted. Model ofcompressor,condenser,evaporator and capillary tube is upbuildedand connected on the basic of sequence of circle and holisticsteady model is founded.Simulation of compressor:Exact process of running ofcompressor is not needed. But the effect to other components ismust be studied exactly. Model of centralized parameter is adopted.Piston compressor is discussed in this article. On the basic ofacademic cycle, actual cycle is used for reference. Precision andconvenience is considered at the same time. hypothesis andpredigestion is necessary before building model of compressor.Simulation of condenser:Thread-tube condenser used inminitype refrigeration and air-conditioning system for example,refrigeratory and so on is discussed. When system is steady,refrigeration enter condenser in state of steam-gas and turn intocoexist state of gas and liquid because of cooling and turn intoliquid subse-quently. For the sake of reflecting characteristic ofcondenser entirely and stability, model of centralized parameter isadopted. Model is composed of heat exchange equation of side ofair and heat exchange equation side of refrigeration. In theprecondition of hypothesis and predigestion, division ofsuperheat,blending ,super-cooling is calculated respectively.Input parameter is size of condenser,parameter of state of air andrefrigerant in entry. Output parameter is parameter of state ofrefrigerant. Simulation of evaporator:Because of characteristic ofgiving out heat, huff-type Condenser is detached division ofsuperheat ,blending. Two kind of heat exchange equation isdiscussed accordingly. And heat exchange performance ofevaporator is calculated. Each division quotiety of heat exchangeand changing rule of quotiety is open out. This means is betterthan single heat exchange equation mentioned in most literature.Input parameter is size of evaporator,parameter of state of air andrefrigerant. Quotiety of heat exchange on side of air and parameterof refrigerant inside of tube is calculated. Output parameter isparameter of enthalpy of refrigerant in exit. Simulation of capillary tube:Choice of capillary tube isrelated with pressure of condensation,state of super-cooling,pressure of evaporation and so on. Means of calculation iscomplicated. Velocity of flow of refrigerant in capillary tube isvery fast. The time of passing is short. State of refrigerant inentrance is instant. So steady state model is adopted.Approximative integral model of adiabatic capillary tube is modelof one dimension flowage with enthalpy and state of refrigerant ischangeless. Bring forward concept of Division of super-cooling...
Keywords/Search Tags:Air-conditioning
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