Design and Performance Study of Large-Angle Inlet Guide Vane with Contraction Channels

Negative inlet pre-swirl has been identified as a potentially effective method to improve the theoretical work that has been performed. However, it should be noted that a large negative inlet swirl may adversely affect the pressure ratio of the compressor due to the different centrifugal forces generated by the movement of the airflow within the large-angle pre-swirl guide vane flow channel. In order to achieve a large inlet negative pre-swirl, a new guide vane with a contraction channel is proposed for a 40° pre-swirl angle fan. This contraction guide vane is of the tandem type, and it includes a first-stage enlarged guide vane and a second-stage contraction guide vane channel. Comprehensive CFD numerical simulations and experimental studies have been conducted to analyze the key design parameters, and the total pressure loss and efficiency of the new guide vanes were analyzed and compared under various operating conditions. It was found that this new guide vane can significantly reduce the total pressure loss coefficients. Compared with the conventional guide vanes, the inlet velocity distribution is more uniform development of inlet velocities, and a significant reduction in flow separation is found for this new guide vane. The guide vane with a ring width ratio of 1.5 reduced 53.11% of the total pressure loss coefficient. In addition, the efficiency of the fan has been shown to increase by more than 2.29% under various operating conditions, due to the improved internal flow of the fan under large flow conditions, under all operating conditions, with an overall improvement in the total pressure ratio of about 5%.