Study On Numerical Simulation And Optimization Of Ventilation For Turbine Building Of Thermal Power Plant

Recently the development of thermal power plant is confronted with the pressure coming from the government, the society and the industry. More abundant energy conservation and emission reduction actions and more comfortable working environment should be conducted or created by thermal power plant under this pattern. As one of the most significant area of building energy conservation and staffs operation, it is with high possibility for turbine building to face the various problems of local high temperature, weak circulation and energy loss, so it is valuable to focus on the research of the property of equipment cooling and ventilation. Several methods have been taken by numerous scholars to research this issue and some improvement suggestions, although most of which are too general, have been concluded. In this thesis field measurement and numerical simulation were combined to analyze and improve the equipment cooling and ventilation. The environment near Row B, which is the area of inspection gallery, was paid more attention to research. A new type of ventilation was introduced and the optimum location, degree and velocity were confirmed respectively, which can provide a large amount of reference to a practical project.Field data collection in three different power plants of three typical climate regions-Jurong, Changchun and Shihezi-was operated and based on the data equipment heat loss was calculated. The results showed the ratio of heat loss of turboset ranked the top, with 60%. Heat pipeline of Changchun power plant and condenser of Shihezi power plant had a high proportion of heat loss. The ventilation volume in operation floor should be increased because of the maximum ratio of heat loss, which reached as many as 64.9%-78.0%, locating in this region. Heat loss of Changchun power plant was restrained in middle floor while that of Shihezi power plant accumulated around the condenser in ground floor and middle floor. Radiation was the main form of heat loss, with the percentage ranging from 60.3% to 71.2%, so it is advisable to control the radiation in order to decrease the heat loss.After simulation in Jurong turbine building, an area of high temperature and weak circulation was confirmed in row B of both ground and operation floor. Opening the grille, operation floor windows and auxiliary air outlet were applied to improve the environment. As the results showed, opening the grille can decrease the temperature of ground floor, opening operation floor windows and auxiliary air outlet had advantages for decreasing operation floor temperature, while opening operation floor windows would increase ground floor temperature, opening auxiliary air outlet would drop the temperature in row B of operation floor more steeply. Introducing the new type ventilation system in hot period, the most effective and energy-saving operation parameters were 1.5m/s venting velocity and 20° venting angle in ground floor and 2.5m/s venting velocity in operation floor.After simulation in Changchun turbine building, an area of high temperature and weak circulation was confirmed in middle floor, while a low temperature area appeared around the side door in row A. Opening the grille can improve the velocity field of ground floor and decrease the temperature in middle floor. Introducing the new type ventilation system to suck the hot air in middle floor and transport it to the cold area in ground floor, a vortex could be created near the condenser and entrain the air nearby with high temperature. Meanwhile it can increase the temperature in cold area around the side door and prevent moisture condensation. 2m/s venting velocity is a sound value considering both energy saving and improvement.After simulation in Shihezi turbine building, most areas had a reasonable temperature except the position adjoining the condenser. This effect was attributed to the proper size and position of grille, reasonable distribution of heat source and the employment of mechanical ventilation. It would improve the high temperature area and decrease radiation heat loss when decreasing the surface temperature of condenser of 10℃, while the improvement for velocity seemed limited. Opening grille on the high temperature area could improve both the temperature and velocity, although the temperature decreasing range could not be as large as the measurement of decreasing condenser temperature, the change in velocity field could compensate the fact. Under winter operation condition, natural ventilation would appear low temperature region, it is acceptable to set the fans blow inside.