外文翻译-蒸发式冷凝器的研究现状及其应用.docx

南华大学机械工程学院毕业设计（论文）附 录1英文原文Research progress and Application of Evaporative CondenserAbstract:Different condensers are introduced, and their characteristics are compared, the structure, principle and characteristics of evaporative condenser are expounded in particular, Application and research of evaporative condenser are analyzed, problems existing in their application are summarized and accordingly the solutions are proposed. Finally, prospect and the further development of evaporative condense are described.Key words: evaporative condenser, Application, Research progress1 forewordWith the development of industry, energy and water resource in China is very nervous, energy is called water, coal, oil and natural gas outside of the fifth energy, and our various industrial process and equipment involved in the process of cooling energy is very serious, the same phenomenon of condensing load, often several times more than foreign consumption of energy. Industrial production in cooling water, cooling water over 70% direct discharge can cause pollution, waste of resources, the current economic and saving has become one of our basic state policy. Evaporative cooling condenser is one of the key equipments recycling, In addition, the energy crisis and water environment and promoting the evaporation of the research and application of the condenser.2 the condenser2.1 air cooling condenserAir cooling condenser for air-cooled condenser, refrigerant coaste heat of the air away by condensation, refrigerants in pipe. Due to the air convection heat transfer coefficient is low, the coil lateral usually add finned heat air side to increase the area. The condenser is small, condensing heat transfer coefficient of higher temperature, pressure, refrigerator, condensation reduced efficiency. Air cooling condensers biggest advantage is not need water, especially suitable for water supply difficult situations or.2.2 water-cooled condenserAs a coolant, make water high temperature and high pressure gas station equipment, called the condensing cooling condenser. The condensing cooling condenser temperature is low, the air-cooled condenser to the refrigeration capacity and operation efficiency are beneficial in domestic and industrial refrigeration systems have been widely applied. The use of condenser cooling water, can a, also can recycle. Because of the shortage of water resources and water. When using circulating cooling towers, need to have such devices, making the water from the condenser cooling, in order to get cooling cycle repeated use. Common water-cooled condenser are horizontal, vertical tube and shell condenser casing tube and shell condenser and condenser, etc.Air and water cooling 2.3 joint condenser 2.3.1Rain water condenserThrough the cooling water flow to the heat sink in water, the group to form the membrane, water evaporation heat can be taken away, and water to show the way have cooled heat. But because the water film, and not in the air blower with high speed under the influence of water flow and heat transfer of evaporation, poor effect. Because of the pipe to keep large distance between the air clear, therefore the condenser covers an area of big, metal consumption, at present the production and use less.2.3.2 evaporation condenserEvaporation condenser evaporation and condensation and sensible heat is based on the two different temperature, fluid (water and air) released when it is hot, evaporation cooling fluid (water), the cooling effect is part of the liquid into steam by heat released evaporation modal and to realize. Evaporation from condenser water tower and improve the operation principle and its water tower basic same, but relatively YuLiang towers, because it saves cooling water in the condenser, condensing heat transfer stage of air temperature ShiQiuWenDu closer, the condensing cooling water condenser temperature is low 3 5 c, it can greatly reduce power consumption, the circulating compressor reduced dosage, only one third of the tower of cold water.Evaporation from heat exchanger, main condenser circulating water system and the air blower three parts. Heat exchanger is part of a group, serpentine hose in a vertical box at the bottom of the cabinet, for water. Irregular pipe evaporation condenser include: (1) heat coil. General light tube condenser evaporation, but with the heat exchange research, elliptic tubes, drops form, corrugated pipe and alternating surface bellows new efficient coil (a) spiral groove, (b) horizontal grain, (c) pierced trough, (d) distortion. (2) fan. Evaporation condenser have air suction type and combined type two kinds, air suction type fan installed in the box on top of the casing pressure is maintained, water evaporation temperature is low, but be in damp air blower, easy cause corrosion. (3) spray water and nozzle. Spray water of water allocation and evenly on condenser water evaporation of heat transfer effect has very big effect. According to experience, spray water to all wet coil, the water surface to form a continuous film for the best, to gain maximum heat transfer coefficient, and reducing the scale. (4) flush boards. Flush boards will heat and moisture in the air, the water blocking with reduce water loss, blow a flush boards to control the loss of water cycle 0.002% 0.2 per cent for total. Evaporation condenser is will enter the heat coil of high temperature and high pressure steam condensate refrigerants. Coil top cloth water system constantly cooling water spray to the serpentine coil, thin layer surface water film, absorb heat tube refrigerants, not part of the evaporation cooling water evaporation tank on to the next cycle, From the bottom of air flows into the box, fan coil heat will evaporate moisture away in the condenser to the top saturated wet air exhaust form.Evaporative cooling air condenser will be transfer and with mass transfer, water-cooled condenser and the cooling tower is the effective integration of condensing equipment structure. Has the following features: (1) water. It takes advantage of latent heat, water vaporizing water-cooled condenser cooling can take every LKG obviously 25. 12kJ calories, and LKG water in the atmosphere will take about 2428kJ evaporation heat and evaporation condenser water for cooling general theory only 1% of condenser, Considering the splash damage, change the water pollution, the actual consumption factors such as water-cooled about the 5% 10%. Evaporation condenser greatly reduces the consumption of water in China, the northern region of water shortage has important significance, (2). Because of air-cooled condenser condensing ability limited environment temperature, and dry ball evaporative condenser, and ShiQiuWenDu limited environment ShiQiuWenDu general than do the ball low temperature 8-14 degrees Celsius, add to the upper fan equipment due to negative environment, therefore, compared with the air-cooled condenser evaporative condenser temperature, low condensation and condensate temperature rise 1 c, each unit of power consumption will increase capacity, so by 3% 3.5% evaporative condenser power-consumption will significantly reduced. Energy-saving effect is obvious. In HVAC system, relative to other condenser can energy 20% 40%, (3) compact structure. Because of the heat and mass transfer process in two evaporative condenser, and not in time, compared with traditional cooling needs with cooling water condenser, more compact structure, (4) dont pollute the environment. Many plant before using shell and tube type or spray condenser, summer because the pressure was too high condensation, often use venting step-down, but not all the time, which is the non-condensable gas containing plenty of ammonia, according to relevant departments, sometimes up to 90% sample analysis, ammonia loss is quite serious, also cause environmental pollution. But with evaporation condenser after nonexistent this phenomenon. This for advocating environmental protection society has the vital significance. Developed countries evaporation condenser used widely.3 research progressResearch progress of 3.1 abroad abroad the evaporative condenser. In 1952, S.G.C huklin is proposed on the generalized evaporative condenser design method 3. Parker and Trey bal of evaporative cooler of heat and mass transfer detailed experimental 4. Leidenfrost and Korenic Parker in Treybal and is conducted on the basis of the mathematical model, the improvement of their spray water flow experiment is carried out 5. Zalewski of condenser water flowed Gryglaszewski and heat transfer performance of the bundle was studied 6. Alonso put forward a general evaporative cooler of heat and mass transfer model 7.The earliest domestic research progress of 3.2 research evaporative cooling technique began in the 1980s, but because of domestic manufacture and application technology of the significance of energy saving, inadequate understanding, this technology in domestic did not cause enough attention, relevant theoretical and experimental research literature is rare. Since the late 1990s, along with the country and the enterprise to the importance of saving energy and unsaturated evaporative cooling technology research, the increasingly more thorough research content also. In the aspect of theory, such as pipe chang jiang walking process of water evaporation cooling cross reference for research object, WangTieJun reflux type tower mathematical model of the thermal calculation, this paper puts forward a quasi-three dimensional calculation method, Define a series of dimensionless parameter, through the calculation of E - got cross-flow NTU relationship chart, Discuss various parameters on its thermodynamic properties and E - NTU relations.4 application situation and deficiencies4.1 application situationEvaporation condenser in western developed countries have more widely used in domestic applications, due to the actual situation of the northwest region water evaporation condenser, extension and application in the northwest, hotels, office buildings, shopping arcade civil building, and the printing, paint shop, computer rooms and other industrial architecture and fresh-keeping, cold storage, storage architecture of agricultural greenhouse such cooling air conditioning equipment basic using evaporative condenser and beer, food, beverage, pharmaceutical, oil and chemical industry, also more and more USES evaporative condenser, according to some of the companys application data shows, the condensing effect is good, saving energy and water characteristic is obvious.4.2 deficiency and the solving methodsThe application of evaporative condenser is increased, in recent years, domestic and foreign research unceasingly thorough, received the good effect. But the evaporation condenser in use process, there exist some problems, to bring some users economic losses. In the application of evaporative condenser main problems in the course of:(1) the scaling problems. Due to evaporation condenser, compact structure, high thermal heat fast, scaling on heat transfer performance influence is considerable. Many factors influence the scaling, heat transfer surface surface temperature and the surface roughness, surface structure, fluid flow, pH value, the fluid temperature, fluid of impurity ions content and plays a very important role. To solve the current anti-scaling method mainly are: 1) chemical method, namely in circulation water, such as adding inhibitor Na5P3O10, soil 6 NaPO3 (as), organophosphate inhibitor (with carbon bisphosphate, carboxyl acid, organic low molecular weight polymer scale inhibitors (polyacrylic acid or sodium salt, etc.; (2) the physical methods, such as magnetic processing technology, electrostatic processing technology, ultrasonic technology and electronic technology, or surface modification also belong to this one; 3) increase evaporation, some appetizers (condenser pipe heat exchanger in order to reduce wet of wall temperature, slow, using the way of increasing pipe gets cold meats, also can have better effect of anti-scaling. Cooling section is at the top of the general on dehydration and adopts copper chips, in order to improve the curl porosity.when and strengthen heat, but even scaling prevention technology, must also be aware, scale removal, such measures adopted can not only improve the heat transfer efficiency of condenser, still can prolong the service life of condenser evaporation.(2) the corrosion problems. Due to evaporation condenser shell in water and air perennial damp environment, easy to corrosion, if severely corrosive, will not only affect the process of production, but will give the production process to bring huge economic losses, thus solving corrosion problems, prolong the service life of heat exchanger. Corrosion of the main measures are: sacrificial anode method, electroless plating method - P, surface coating material handling, change etc.(3) the reasonable distribution of water. Spray water quantity selection and distribution of evaporative condenser heat effects are significant, spray water unit width of general with cooling water to the domestic and foreign products, inferior product performance compared with foreign products, small volume, and spray evenly, the current domestic enough in this aspect, make water literature should be further reasonable matching theory research. In water distribution system, using large prevent type sprinkler mouth, instead of numerous blowhole, can greatly simplified water distribution system, improve the efficiency and reliable operation, easy maintenance and maintenance costs reduced.(4) fan. Previous domestic evaporation condenser is blowback structure, fan installed below, due to improper setting flush boards, or user improper operation, first, after the pump drive fan fan motor, make water short-circuit boxes to burn. Now, by air suction type, avoid the junction box in case contact with water, and generally does not exist, but the higher requirements for fan blades, ability corrosion.(5) the problem of vibration and noise. Evaporation condenser runtime noise from four aspects: the main water, water pump, fan noise and the comprehensive noise falling. One fan noise. The noise of the fan blades, can choose low noise design width of axial flow fan and increase exhaust muffler. The noise, can be used to drop down noise reduction, the muffler blanket to eliminate noise can be use sound-absorbing material. Due to the tube bundle go high pressure gas, if not firm, fixed by high-pressure air impact, easy to occur, and the larger vibration noise. Therefore, we should pay attention to bundle and cabinet, also can consider the case in the retaining bolt based on channel shock springs to reduce the noise is used.(6) maintenance problems. Evaporation condenser for maintenance requirement is relative taller, the user needs regular maintenance. The algae in the heat accumulation of surface to reduce heat transfer efficiency;, In addition, corps bacteria also is a kind of harmful microbes, send out to the water in the air of respiratory tract and lungs to produce infection. So must be cleaned regularly tank to ensure quality requirements, sundry to prevent algae and corps bacteria.5 development prospectsThe development of evaporative condensers should pay attention to the theory of the first, seek innovation and perfection of the new theory.In tubular evaporation condenser, in order to improve the performance of condensing equipment, except on the structure change of tube type, the research also evaporation condenser manufacturer innovate improve equipment performance of a major way. With the deepening of the research, strengthen the pipe type more and more, in this to distort tube, for example, as a new element, its internal heat distortion of the spiral flow with vertical tube fluid to rotate and secondary flow as the main characteristics of strong disturbance, make the tube temperature gradient in radial flow to produce large mixed, wall temperature gradient, so as to realize the heat transfer enhancement. Visible by strengthening the pipe is currently an important developing direction. Water flows from tube membrane surface, the surface tension of contraction, cannot be observed. In addition, in seawater desalination field, with the same principle of evaporative plate condenser can also unto this kind type, but also can be used for condenser evaporation refrigeration field, its structure is more compact, is more suitable for small and medium-sized commercial air conditioning system, especially the field. In order to improve the heat transfer performance, can use surface heat structure, it can improve the flow condition, strengthen water and air between the heat and mass transfer process, greatly enhances the heat and heat transfer performance, and the heat on the special structure of itself to finish, do not need any additional maintenance. All kinds of heat plate condenser evaporation of signal before condensation coil is used mostly hot-dip zinc to prevent corrosion problems, in recent years, China has some manufacturers of condensing coil used stainless steel materials, basically solved the problem of corrosion, and greatly prolong the life, reduce weighed more than 20%. From the lower production cost, reduce corrosion and reduce the quality into consideration, stainless steel material is evaporative condenser condensing coil a development direction. For the development of Chinese evaporative condenser, should focus on the exploration of the condenser evaporation principle and design ideas, with Chinas national conditions and the introduction of advanced manufacturing technology, this theory can compensate for our shortcomings, make us in a relatively short period of time to achieve higher level of development. In addition