毕业论文移动版

摘要：电水动力学 EHD(electro hydrodynamic)强化换热是指在换热表面的流体中 施加一电场，利用电场、流场和温度场之间的相互作用达到强化传热效果的一门 新型传热强化技术。为了进一步探索电场对汽泡影响所带来的强化传热作用和机理，本课题针对均匀电场下气泡周围电场分布状况进行研究。选用了R410A工质，利用 ANSYS 计算软件，编程求解出不同电场作用下气泡周围场强分布特性。分别向上极板施加 15kv,20kv,25kv 的直流高压电场，对单个气泡附壁、脱离及多个气泡生成并部分脱离时电场分布特性进行了数值模拟。电场使气泡运动规律和行为特征发生改变，从而改变流场结构，并使热量的传递得到强化，所以气泡起着核心纽带作用。但是，因为电场和热流场相互干涉影响，所以气泡行为及运动规律等内容的研究，成为电场强化传热技术研究的难点与重点。81427

毕业论文关键词：电水动力学;均匀电场;数值模拟;流场结构

India HVAC&R Goes Global

Abstract:  The total market size in 2008 for the HVAC&R industry in India was approximately $2。5 billion。 That year, India produced roughly 5 million refrigerators,2。5 million room air conditioners, packaged air conditioners of various capacities, and packaged chillers of reciprocating, scroll, screw and absorption types。Other HVAC&R products manufactured in India include air-handling units, fan-coil units, refrigeration systems for cold rooms and freezer rooms; low-temperature brine chillers for industry; and commercial refrigeration equipment for food stores and supermarkets。 The following stories describe some Indian companies that are making their mark internationally。Heat Pumps in DenmarkThermax absorption heat pumps and chillers are finding increasing acceptance with European and U。S。 clients that want energy-efficient equipment。 Businesses are demanding systems that can reduce carbon emissions and help cope with global warming。Over the last decade, Thermax has worked in optimizing energy use in Denmark by installing absorption heat pumps for centralized heating, which is a reverse application of centralized cooling with absorption chillers。 Hot water from a central generation facility is used for space heating in town buildings。 The heating companies reduce the energy intensity at generating centers by tapping low-grade heat from other sources such as geothermal heat from sandstone aquifers or waste heat from townSince its first installation in 1999, Thermax absorption heat pumps are operating in several district heating installations。 Recently, the company is fulfilling an order for a 3。4 MW steam absorption chiller to be installed in downtown Copenhagen as part of a district cooling project。 The total capacity of the plant is 15 MW, which uses the output of the Thermax chiller, free cooling using seawater and ammonia chillers。 The plant will save approximately 2,500 tons (2268 Mg) of carbon dioxide per year。In Spain, Thermax has commissioned chillers in hotels and office buildings that run on water heated by solar panels。 Clients elsewhere in Europe also use Thermax chillers that work onexhaust gas from fuel cells or excess steam from old boilers that use wood waste。In the United Kingdom, large retailer Tesco has installed Thermax chillers at two stores as part of a plan to reduce its carbon footprint through various measures, including using energy-saving devices。 The chillers use water from the cogeneration system that Tesco has installed for generating power。In the United States, a 1,100 kW test engine installed at a plant of a leading plastics manufacturer in Ohio generated a great deal of waste heat。 Thermax harnessed this waste heat to drive an absorption chiller。 Waste heat is converted to energy savings as chilled water from this system is used for process cooling in the plant。 More than 150 business customers in the United States are gaining from energy profits and green reputations by installing Thermax chillers。 Recently, the University at Albany-State University of New York，replaced its old, inefficient cooling system with a 1,400 ton (4924 kW) chiller that works on hot water。 The university has gained 35% energy efficiency with substantial savings in operating and maintenance costs。 The Henry Ford Museum in Detroit and Colorado School of Mines in Golden, Colo。, also have Thermax chillers。Under a recent strategic agreement, Trane, a leading global indoor comfort systems and service provider for the North American market, will source and distribute Thermax chillers。 (责任编辑：qin)