A detailed investigation of a variable nozzle turbine with novel forepart rotation guide vane

Abstract

One of the disadvantages of a variable nozzle turbine in practical application is the stage performance degradation due to nozzle endwall leakage flow at small nozzle openings. Aiming at restricting the nozzle leakage flow rate to improve turbine stage performance, a novel forepart rotation guide vane has been proposed and numerically studied in present work. First, the numerical results of baseline turbine were validated by experimental data to ensure the accuracy of numerical methods. Then steady and unsteady simulations were performed on both baseline and forepart rotation guide vane turbines to demonstrate the effectiveness of the novel vane and to study the characteristics of nozzle leakage flow, respectively. Results indicate that there is up to 13.5% peak efficiency improvement that has been achieved at 10% nozzle opening with the forepart rotation guide vane design; besides, rotor–stator interaction for forepart rotation guide vane is also mitigated due to the reduced nozzle leakage flow rate, thus the intensity of loading fluctuation on rotor blades is weakened significantly, which is beneficial to improve rotor blade forced response.

An evaluation method for transient response performance of a turbocharger in gasoline engine: Simulation and experiment

“…Therefore, it is relatively difficult to accurately measure the instantaneous efficiency of a turbine . 13 While obtaining the required parameters in Dx is relatively easy. This equation (9) indicates that in the acceleration process, the increment in mass flow rate at compressor outlet driven by the energy increment at turbine inlet has a unit of g/(kJ⋅s) and a large value of Dx indicates the good transient response performance of the turbocharger.…”

“…Huang R et al 13 optimized the acceleration parameter B from the perspective of the ratio of the rotor kinetic energy provided by the turbine to the engine exhaust energy absorbed by the turbocharger, and then proposed the acceleration parameter A. Parameter A applies to the acceleration conditions when the turbocharged ICE is promoted from low power working condition to high power working condition. Moreover, the acceleration parameter A must be obtained under the working conditions of ICEs.…”

Compressed air energy storage system: Effect of variable relative stator installation angle on nozzle governing turbine performance

“…The idea of a "stepped spherical endwall" was put forth by Gao et al [28] and enables the stator's clearance to remain constant at various SIA while drastically lowering leakage losses. Researchers have also "split" the stator in addition to altering the by adopting a forward rotating stator design with a 10 % nozzle opening, the peak turbine efficiency could be raised by 13.5 % [29]. The peak turbine efficiency may be successfully boosted by 8 % at a nozzle opening of 6 % thanks to their new split sliding stator suggestion [30].…”