Applied Mechanics and Materials Vols. 501-504

Abstract: On the basis of analysis of the principle of thermoelectric refrigeration and the research on the thermoelectric refrigeration technology and the thermal theoretical analysis of electronic components by domestic and foreign scholars, research on thermoelectric cooling of the uniform heat packaging surface from both the surface integral heat radiating and the local hot spot cooling of the chip by finite element numerical simulation and cooling both the chip and the heat from the whole surface of the local hot spots, using the finite element method of numerical simulation techniques Package uniform surface heat thermoelectric cooling study found the thermoelectric cooling hot surfaces in a uniform local cooling effect and temperature distribution, and pointed out that the chip thermoelectric cooling and thermal design layout surface will be in the future to improve the electroniccomponents of a hot heat important research direction.

Abstract: The method of numerical simulation was adopted in this study to explore the size of the natural ventilation inlet opening, outdoor temperature and ambient wind speed and other environmental parameters to effect of the varied rules of thermal environment of the strawberry solar greenhouse. The variation of outdoor air temperature effected greatly to the indoor thermal environment, the average air velocity in the strawberry growing zoon within the greenhouse was rose initially and dropped tend to the steady with increasing outdoor air temperature. The average temperature in the strawberry growing zoon was decreased with increasing the outside wind speed. The average air velocity was increased gradually in the strawberry growing zoon within the greenhouse with increasing outdoor wind speed. The average velocity was reduced gradually toward to constant.

Abstract: The performance of a solar-driven air-cooled ejector refrigeration system using ammonia as refrigerant with rated cooling capacity of 10.5kW was analyzed for air-conditioning purpose. The cooling capacity of the proposed system increases with the rising of indoor temperature and enhancement of solar irradiance, while decreases with the rising of outdoor temperature. The COP has similar changing trend with that of the cooling capacity except that it increases rapidly with the enhancement of solar irradiance firstlyand then become stable by and large after solar irradiance exceeding a certain value. The cooling capacity is 6.3~52kW and the COP 0.06~0.11 under the normal operating conditions with indoor temperature over 27, outdoor temperature below 38°C and solar irradiance surpassing 500 W/m². The proposed system can match the climatic conditions in air-conditioning season of Nanning, a typical city in hot summer and warm winter region.

Abstract: The optimal design for exhausted ducting mode and internal structure in direct cooling exhausted duct system influence every steam to assign the flow obstruction and flow while managing to assign directly.The flowing filed of steam in direct air cooling exhausted duct for 1000MW power generating unit is simulated via Computational Fluid Dynamics(CFD) software under typical steam turbine conditions,and the best chamfer angle can be get by adding different chamfer angles in back of exhaust pipe.The result shows that the steam flows through each distribution pipe with balanced flow under the condition of chamfer angle of 30 °and the flow resistance is much lower than before

Abstract: Currently, most of the domestic fertilizer unit, granulation tower basically using natural ventilation, granulation tower granulation process is ejected molten urine through the nozzle to cool down after melt crystallization (phase transition), cooling 3 process^[1]. The beginning step is cooling stage of liquid urea. The second step is liquid urea into solid urea particles. The last step is solid urea paticles cooling process with long drop distance. In the process of landing urea crystals, the releasing heat is taken into the cold air. The average air rate of natural ventilation in the tower is 0.4-0.8m/s. And the air rate of mechanical ventilation prilling tower is 0.6-1.2m/s. Landing time of urea particles from nozzle to Scraper is about 5-10m/s.

Abstract: This paper presents statistical analysis results of wind speed and atmospheric turbulence data measured from a meteorological station in Beijing and is primarily intended to provide useful information on boundary layer wind characteristics for wind-resistant design of tall buildings and high-rise structures. Wind velocity data in longitudinal, lateral and vertical directions, which were recorded from an ultrasonic anemometer during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of existing theoretical and empirical models. The objective of this study is to investigate the profiles of mean wind speed and atmospheric turbulence characteristics over a typical urban area.

Abstract: The isolation wards should use the reasonable air distribution to control the distribution and elimination speed of the contaminant. This paper will simulate the distribution of the carrier particles in the wards under the condition of different ventilation rates and air distribution and the change rules of the remaining particles with the time by building a ward model with unsteady stated contaminant source. The simulation results show that all the factors like the arrangement of the air inlets, the ventilation rates, the amounts of the air outlets could affect the capacity of the air distribution to eliminate contaminants, among which the effect of the ventilation rates is the most remarkable. The conclusion also proves that using the CFD technology to simulate could have great guiding significance on determining the various form factors of the air distributions in the wards.

Abstract: Natural convective heat transfer is the most important means to supply heat load for resident building to keep necessary indoor air temperature in winter. To determine the surface convective heat transfer coefficient (CHTC) of a radiator is of primary importance to evaluate the heat flow within building interiors, and thereby to affect the thermal comfort and the overall energy consumption of a building. In this paper, a turbulent k-ε model is used to numerically analyze the heat transfer characteristics of a radiator used in a heating room in Lanzhou region of China. The results indicate that the averaged Nu number of radiator surface increases with increasing outer wall thermal conductivity, decreasing outdoor temperature and decreasing radiator surface area, respectively. And the outer wall thermal conductivity has weak influence on the local Nu number of radiator surface.

Abstract: This paper analyses the method of how to select the coefficient of cooling load caused by indoor heat source (including equipment, lighting and personnel) and solar heat gain, which provides a basis for the correct calculation of air condition cooling load.

Abstract: Based on the climate characteristics of the region which is hot in summer and cold in winter , this article introduces a solar energy heating technology, taking Hangzhou as an example and combining the theory of building energy efficiency. It is a collector-tank-double pump cycle of floor heating system, combining solar heating system with solar hot water system. Collectors are concentrating vacuum tube collectors, which can efficiently use solar energy. Combining solar collector with the building integration, we can use solar energy resources, and it can play shading effect.