Pressure drop analysis and aerodynamic design of compressor L-inlet duct

Pressure drop inside the compressor L-inlet duct (CLID) has a great impact on the intake loss, which directly affects the operating cost of the power plant. Generally, every 500 Pa inlet pressure drop is equivalent to 0.5% intake loss at standard conditions, which can contribute to higher than 1% of gas turbine power loss in terms of fuel flow. Hence, the pressure drop should be kept as low as possible. Pressure drop that occurs within the CLID mainly depends on the structural parameters, however, no general design guidelines were found in open literature. Moreover, a reasonable intake duct aerodynamic design is the fundamental solution to the problem of compressor inlet distortion. Therefore, in this paper, the fluid dynamics of CLID are revealed by using both the experimental and numerical methods. Then, the effects of typical parameters on the pressure drop and total pressure loss coefficient are investigated. Furthermore, the conceptual design of CLID is proposed on the basis of distortion flow analysis and 1D intake volute design. The results show that larger CLID width (a/D4) and depth (b/D4) result in larger flow separation at the contraction, thereby leading to smaller total pressure drop and total pressure loss coefficient. However, the opposite change occurs at the cone diameter (D0/D4). Besides, the conceptual design of CLID is proposed by indirectly establishing the relationship between the outlet flow angle and inlet structural parameters.