| Nowadays, the country planning requires energy saving and emission reduction, the architecture has wasted lots of resources in construction and usage. A large amount of afterheat, wet air and harmful gas were brought out by inner heat produced in the manufacture process, for its voluminous capacity, which affect workers'environment. If mechanical air exhaust was applied to solve these unfavorable elements, lots of energy will be consumed. Natural draft can vent air in large quantity, and improve the internal hot environment. As a zero energy consumption method, it can save energy as well as reduce the environment contamination. With the demand of better quality and better life, the request for better workshop environment is also pressing its way. Many workshops choose the natural draft method to save the cost, however, the workshop designers only carry out the design according to their personal experience, and the actual testing numerical value of ventilation is not quite good.Because of Iron and steel plant have large internal heat source, it derived the form of ventilation from the principles of natural ventilation mainly depend on the form of hot air. In order to avoid the phenomena of shortness of breath into the flow, and it should be located the neutral surface near the heat source, and lower the height of Neutral surface, anywhile the lower neutral surface can make the fresh air outdoors take away the waste heat as its flow away .Lower the position of the neutral surface could be achieved by increasing the elevation of imports and the exhaust port which will makes the exhaust pressures increased, it also means decreasing the area of the exhaust port determining the size of exhaust port area play a role in cutting down the cost of civil engineering. It's self-evident that determine the parameters such as the height and area of inlet and outlet as a greater significance before the plant design. To insure reduce the project cost, how to make the plant reaches good effect of natural ventilation is the main purpose of the research which will play a guiding role in the theory for the design of the plant.Contrary to the steel industry's major plants, the research uses CFD technology to simulate the natural ventilation process of the plant, make use of the standard k- turbulence model to simulate the different sections of the plant's temperature and velocity fields. simulate the actual value of the contrast compared with the measured data verify the reliability of the model, while through analysis the internal ventilation of plant problems, it presented optimization advice compared to the measured data.In research of the four plants, the author finally select a factory with poor ventilation as a typical case to optimize the transformation. After numerical simulation, founding that the plant inlet and exhaust port design is unreasonable. This paper proposes improvement proposal with the exhaust port of the elevation and area, the first and third improvement proposal respectively for optimizing the exhaust port of the elevation and area and respectively for changing the row, obtain the result of changing in the elevation of the inlet in different sections of temperature, and find to improve the height of the exhaust port in favor of natural ventilation plant which is consistent with the literature.The second and the four categories for the row, the optimization of air inlet area, changing the area of the exhaust port and obtain the changes in different sections of temperature and plant velocity could obtain optimization. with four different Optimal conditions, it could obtain the best proposal of the natural ventilation plant design. The results of research provides a theoretical basis for the design of the exhaust port and also have some theoretical guidance and practical significance for achieving the industrial energy conservation and building green iron and steel enterprises... |
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