| At present,the power consumption of China is growing rapidly.In order to reduce environmental pollution,gas turbines fueled by emerging clean energy natural gas have developed rapidly,increasing the status of gas power generation in the power system.However,the performance of the gas turbine is largely affected by the temperature of the inlet air,and when the temperature of the inlet air decreases,the power generation capacity and thermal efficiency of the gas turbine will increase.Therefore,the performance of the gas turbine can be improved by installing an air intake cooling system at the front of the compressor.Among many intake air cooling methods,direct evaporative cooling only needs to use water as the cooling source,which has the advantages of less investment requirements,environmental friendliness and low energy consumption.Therefore,the gas turbine inlet evaporative cooling system is determined as the research object of this paper.And the main work and conclusions are as follows:Firstly,by analyzing the energy changes of various parts of the gas turbine cycle during operation,it is theoretically illustrated that the reduction of the compressor inlet temperature is necessary to improve the performance of the gas turbine.Based on the analysis of the working principle of direct evaporative cooling equipment,the main influencing factors of direct evaporative cooling performance were studied by establishing a calculation model for the direct evaporative cooling process.Secondly,the direct evaporative cooling section of the gas turbine inlet evaporative cooling system was studied experimentally.At the same time,the Fluent software was used to simulate the change of the temperature field on the simplified filler surface.By comparison,the results obtained by simulation and experiment are basically the same:(1)When other parameters are fixed and the water flow rate increases from 0.01m/s to0.4m/s,the outlet temperature of air decreases with the increase of the water flow rate.But the change of water flow rate has little effect on the outlet temperature,and the increase of the water velocity will also cause the uneven distribution of the water flow,resulting in poor cooling effect.Therefore,the water flow rate can only be increased appropriately,and should be controlled at 0.1 m/s?0.2 m/s;(2)When other parameters are fixed and the intake air velocity changes between 1.6m/s?3.2 m/s,the increase in the air velocity will increase the mass transfer coefficient andmake the cooling effect better.However,the changing wind velocity will cause the contact time between air and water to become shorter,thereby reducing the cooling performance.According to simulations and experiments,the effect of wind velocity on the contact time between air and water is greater than that on the mass transfer coefficient,and the wind speed should be controlled at 2.2 m/s?2.6 m/s;(3)When other parameters are fixed and the intake air temperature rises from 30°C to39°C,the relative humidity decreases.Both the average outlet temperature and the temperature drop between the inlet and outlet air increase with the increase of the air intake temperature,but the evaporative cooling efficiency changes less.It can be inferred that the air has higher cooling potential under the environment of high temperature and low relative humidity.Finally,taking Quanzhou as an example,the effectiveness of the intake evaporative cooling system was analyzed based on the change of the parameters of the gas turbine before and after installing the direct evaporative cooling air intake system.The data shows that the power plant in the case had 7236 hours to meet the requirements for operating the intake cooling system during the year when the direct evaporative cooling air intake system was installed,accounting for 87.1% of the total duration of the year.In addition,compared with the original gas turbine,the monthly gas inlet temperature of the improved gas turbine has been reduced by 3.6°C?9.7°C,the annual power generation has increased by 37380MW·h,and the revenue has reached 867,000,which has a high economic efficiency. |
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