The performance of fan stage in a small turbofan engines is significantly affected at high-altitude low Reynolds number. In order to examine the effect of low Reynolds number on the fan stage, 3D numerical simulation ...The performance of fan stage in a small turbofan engines is significantly affected at high-altitude low Reynolds number. In order to examine the effect of low Reynolds number on the fan stage, 3D numerical simulation method was employed to analyse the performance variations and the underlying flow structure in the fan stage. For the sake of decreasing the influence of low Reynolds number, the different bowed stator airfoils were redesigned and the effect of the modified design was evaluated.展开更多
The demand of further increasing bypass ratio of aeroengine will lead to low pressure turbines with higher diameter. Therefore, it is necessary to design a duct to guide the hot gas flow which is expelled from the ups...The demand of further increasing bypass ratio of aeroengine will lead to low pressure turbines with higher diameter. Therefore, it is necessary to design a duct to guide the hot gas flow which is expelled from the upstream high pressure (HP) turbine stage to the downstream low pressure (LP) turbine stage. Named by its position, this kind of duct is always called intermediate turbine ducts (ITDs). Due to the pursuit of higher thrust ratio of the aeroengine, this kind of ITDs has to beas short as possible which leads to aggressive (high diffusion) S-shaped ITDs' geometry. In this paper, two different schemes of high diffusion separation-free S-shaped ITDs were studied with the aid of three-dimensional CFD programs. Although these two ITDs have the same area ratios (AR), because of the different duct length, they have totally different area as well as area change rates. With the detailed calculation results, comparisons were made to investigate the underneath physical mechanisms. Additionally, a direct estimation of the ITDs' loss is given at the end of this paper and some ITDs' novel design idea is proposed to initiate some further discussions.展开更多
A heavy-duty gas turbine,designed for natural gas,was used to bum the syngas with two different calorific values.This study was mainly to optimize the flow matching scheme for the gas turbine.Two models of gas turbine...A heavy-duty gas turbine,designed for natural gas,was used to bum the syngas with two different calorific values.This study was mainly to optimize the flow matching scheme for the gas turbine.Two models of gas turbine burning syngas with different calorific values were established and the calculation models of different flow matching schemes were provided.The optimum scheme was obtained by evaluating thermal efficiency and work output under different operating conditions.The results showed that the highest unit efficiency was achieved by,without significant drop in work output,increasing the throat area of the turbine nozzle and reducing the initial temperature of the gas.On the premise of ensuring the safety of the gas turbine unit,increasing the pressure ratio of the compressor could further improve the unit efficiency and the work output.Simply adjusting the angle of the inlet guide vane fails to match the flow of compressor and turbine.The measures such as reducing inlet temperature of turbine or air bleed still need to be adopted,but the thermal efficiency dropped significantly in this process.展开更多
文摘The performance of fan stage in a small turbofan engines is significantly affected at high-altitude low Reynolds number. In order to examine the effect of low Reynolds number on the fan stage, 3D numerical simulation method was employed to analyse the performance variations and the underlying flow structure in the fan stage. For the sake of decreasing the influence of low Reynolds number, the different bowed stator airfoils were redesigned and the effect of the modified design was evaluated.
文摘The demand of further increasing bypass ratio of aeroengine will lead to low pressure turbines with higher diameter. Therefore, it is necessary to design a duct to guide the hot gas flow which is expelled from the upstream high pressure (HP) turbine stage to the downstream low pressure (LP) turbine stage. Named by its position, this kind of duct is always called intermediate turbine ducts (ITDs). Due to the pursuit of higher thrust ratio of the aeroengine, this kind of ITDs has to beas short as possible which leads to aggressive (high diffusion) S-shaped ITDs' geometry. In this paper, two different schemes of high diffusion separation-free S-shaped ITDs were studied with the aid of three-dimensional CFD programs. Although these two ITDs have the same area ratios (AR), because of the different duct length, they have totally different area as well as area change rates. With the detailed calculation results, comparisons were made to investigate the underneath physical mechanisms. Additionally, a direct estimation of the ITDs' loss is given at the end of this paper and some ITDs' novel design idea is proposed to initiate some further discussions.
基金This work was support by the National Natural Science Foundation of China(Grant No.51976214 and No.51576193)National Science and Technology Major Project(2017-V-0010-0001 and 2017-IV-0100-0047).
文摘A heavy-duty gas turbine,designed for natural gas,was used to bum the syngas with two different calorific values.This study was mainly to optimize the flow matching scheme for the gas turbine.Two models of gas turbine burning syngas with different calorific values were established and the calculation models of different flow matching schemes were provided.The optimum scheme was obtained by evaluating thermal efficiency and work output under different operating conditions.The results showed that the highest unit efficiency was achieved by,without significant drop in work output,increasing the throat area of the turbine nozzle and reducing the initial temperature of the gas.On the premise of ensuring the safety of the gas turbine unit,increasing the pressure ratio of the compressor could further improve the unit efficiency and the work output.Simply adjusting the angle of the inlet guide vane fails to match the flow of compressor and turbine.The measures such as reducing inlet temperature of turbine or air bleed still need to be adopted,but the thermal efficiency dropped significantly in this process.
