Research on the Performance of Pumpjet Propulsor of Different Scales

Jun Yang,Xianzhou Wang,Liwei Liu,Dakui Feng,Chaobang Yao

doi:10.3390/jmse10010078

Jun Yang, Xianzhou Wang + Show 3 more

Open Access

https://doi.org/10.3390/jmse10010078

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Abstract

This study presents a numerical research on the open-water performance of a pumpjet propulsor at different scales. Simulations were performed by an in-house viscous CFD (Computational Fluid Dynamic) code. The Reynolds-averaged Navier–Stokes (RANS) method with SST k-ω turbulence model is employed. A dynamic overset grid is used to treat the relative motion between the rotor and other parts. The numerical results are compared with the model test data and they agree well. Comparisons for the open-water performance between the pumpjet propulsors with two scales are carried out. The results indicate that the total thrust coefficient of the large-scale pumpjet propulsor is greater than that of the small-scale one while the torque coefficient is smaller. Therefore, the efficiency of the large-scale pumpjet propulsor is about 8~10% higher than that of the small-scale pumpjet propulsor. The open-water performance of the rotor, pre-swirl stator and duct is obtained separately to estimate the discrepancies on the thrust and torque coefficients between different scales. To analyze the scale effect from different parts, the research on flow field and pressure distribution are carried out. The variation of total thrust and torque coefficient comes mainly from the rotor, which is caused by the flow field, influenced by the duct and stator.

Highlights

In recent years, with the rapid development of computer technology, CFD technology has become more and more mature
Gaggero [3] designed a rim-driven thruster using a CFD-based approach and Liu and Vanierschot [4] compared hydrodynamic characteristics between a ducted propeller and a rim-driven thruster with the help of the CFD method. These appear to tell us that CFD technology can give detailed information about the flow field
Sánchez-Caja et al [10] present a numerical study about scale effects on performance coefficients for a CLT propeller using RANS (Reynolds-averaged Navier–Stokes) code FINFLO

Summary

Introduction

With the rapid development of computer technology, CFD technology has become more and more mature. With the maturity of the theory, the CFD method has been carried out to study 3D turbulent flow and predict the performance of rotating machinery such as by Gong et al [1] and Zhang et al [2] They performed numerical analysis on the wake of the ducted propeller. Many scholars have used the CFD method to research the scale effect of a propeller. Results show that scale effects of the propeller performance are mainly caused by different boundary-layer flows. Sánchez-Caja et al [10] present a numerical study about scale effects on performance coefficients for a CLT (contracted and loaded tip) propeller using RANS (Reynolds-averaged Navier–Stokes) code FINFLO. Many scholars have used the CFD method to predict the performance of model-scale pumpjet propulsors. The effect of grid refinements is evaluated by the grid convergence index (GCI) like the small-scale pumpjet propulsor. The medium grid and medium time step are selected as the uncertainty is small enough

Study on the Effect of the Wall Function Model

Results and Discussion

Difference About the Rotor