A Practical Axial Compressor Design Optimization Approach Based on Gas Turbine Operation

Abstract

In the current study, it is focused on blade optimization of compressor to achieve improved performance characteristics. Due to dependency of mass flow rate on the inlet temperature of the gas turbine, temperature changes influence on compressor performance and efficiency. In order to enhance the working conditions at design and off-design operation, an automated design process is applied. The process has three main steps including parametrization of the geometry, numerical simulation of flow and optimization design approach. Stochastic design approach is utilized for optimization. The objective of this improvement will push the airfoil geometry in a way that minimum loss value, extended acceptable off-design operation in constant exit flow angle can be achieved with being focused on hot day's operation. The considered case in the present study is a compressor of MGT-70 heavy-duty gas turbine and the optimization focuses on the first four stages. Based on numerical simulation of optimized compressor, 1% enhancement in efficiency in all operating conditions is achievable. Moreover, the mass flow rate can be enhanced roughly up to 0.8% and 1% for design and off-design conditions, respectively. After assembling the new developed parts, the first upgraded prototype of the gas turbine has been tested in sixth Unit of Parand power station. More than 600 signals of pressure and temperature in circumferential and radial directions were extracted from compressor section. The results show good agreement predicted in range inlet flow angle between measurements and theoretical targets.

CFD-based blade shape optimization of MGT-70(3)axial flow compressor

“…It means that in off-design operation, it is possible to have earlier local stall. This can easily happen when the machine works at high ambient temperature in summer days (Pakatchian et al, 2015). To prevent this unfavorable event, the OBF has changed; consequently, the cascade geometry can have acceptable performance toward the stall condition.…”