Design And Analysis For Blades Of Turbines In Solar Chimney Power Plants With Vertical Collectors

The flow and heat-transfer characteristic of solar chimney power plants with vertical collectors was analyzed. The results show that the most energy of hot air in the system are thermal energy and kinetic energy, and kinetic energy is the main part. So, the design principle of wind turbines was used to design the turbines of system and numerical computation method was used to analyze performance of the turbine model. Experiments were also made to analyzed performance of the turbine.After comparing many wind turbine types, the CLARK Y airfoil profile was selected to design a turbine with 6 blades based on the wind turbine design theory. And the SST k-co turbulent model and MRF were used in the numerical computation, of which purpose is to analyze the turbine model. The result shows that the designed turbine could convert kinetic energy and pressure energy of hot air to mechanical energy, but the efficiency of the latter is low. Then, airfoil profile, installation angle and torsion angle, and the camber of the turbine blades were optimized. The results of numerical computation show that the output power of turbine improved increases by 12%,20% and 11% accordingly. And the results also show that the best airfoil profile is NACA4412 type, the best installation angle is 40° and the best torsion angle is 20°. The energy conversion efficiency of turbine also improves significantly after optimization.The experiments were carried out to analyze the optimized turbine models by using the low-speed wind tunnel. The results show that the output power of turbine increases by 14%、23.3%、9.5% when its airfoil profile, installation angle and torsion angle,and camber of blades are optimized, and the optimized turbine could convert more kinetic energy and pressure energy of hot air to mechanical energy. Turbines with different numbers of blades were tested, and results display that when the wind speed is less than 12m/s, turbine with 10 blades has higher conversion efficiency. But the turbine with 9 blades has the maximal power with the wind speed increases.The results of numerical computation were verified by the experimental results. The result shows that the conversion efficiency of turbine is improved by optimizating, but the errors between output powers of turbine in numerical computation and the corresponding values in experiments are large. This is because, firstly, the hot air temperature in experiments is constant which is different from the actual operation condition in which the hot air temperature is higher than the environment temperature. Secondly, the rotate speeds of turbine in numerical computation are not accurate enough. Even so, the turbine for the solar chimney power plants with vertical collectors which is designed based on the wind turbine could convert the kinetic energy and power energy of hot air to mechanical energy. This could also offer some references for analyzing the turbine of the system.