Research on Blade Thickness Influencing Pump as Turbine

Abstract

Research on the efficiency improvement of pump as turbine (PAT) is inadequate. Blade thickness is an important geometry parameter in blade design. To explore effects of blade thickness on the influence of PAT, numerical research on three different specific speeds of PATs with different blade thickness was carried out. Their performance changes with blade thickness were presented. Besides, the variations of hydraulic loss distribution with increasing blade thickness were performed. Theoretical analysis gives a reasonable explanation for the performance change. Results show that PAT's flow versus efficiency curve ( -) is lowered; flow versus head ( -) curve and flow versus power ( -) curve are increased with increasing blade thickness. The increase of -is mainly attributed to the increase of theoretical head caused by increasing blockage of impeller inlet area. Hydraulic loss distribution analysis indicates that the total hydraulic loss within PAT is increased with increasing blade thickness. The increase of -curve is a combined effect of the increase in theoretical head and the total hydraulic loss. The decrease of efficiency with increasing blade thickness indicates that the blade thickness of PAT should be as thin as possible if its strength could be met.

Performance Prediction and Geometry Optimization for Application of Pump as Turbine: A Review

“…The influence of blade thickness on PAT performance has also been investigated (Yang et al, 2014). The results show that increasing blade thickness can lead to decline of efficiency and rise of head and shaft power.…”

Analysis of Applicability of CFD Numerical Studies Applied to Problem When Pump Working as Turbine

“…Outlet [47] static pressure mass flow η 6.8 [49] uniform velocity constant static pressure H 9 [51] --Q 0.82 [52] velocity inlet static pressure η 8.70 [53] total pressure mass flow H 3.70 [54] static pressure mass flow η 7.69 [55] velocity inlet pressure outlet η 3.99 [56] velocity inlet pressure outlet -- [69] total pressure environmental pressure -- [58] mass flow --- [50] mass flow -H 4.81 [59] pressure mass flow η 4.64 [60] constant total pressure variable static ψ 4.00 [61] pressure inlet pressure outlet p 28.60 [62] static pressure mass flow P 12.31 [63] static pressure mass flow -- [64] mass flow static pressure P 14.71 [65] static pressure mass flow η 4.17 [66] --H 10.00 [67] velocity static pressure H 10.70 [68] volumetric flow rate average static pressure ψ 5.00 [70] enviromental pressure 1bar mass flow -- [71] static pressure mass flow -- [72] mass flow static pressure ψ - [73] total pressure flow rate η,ψ (design point) 4.9 [43] mass flow, velocity direction, turbulence kinetic energy k and turbulent dissipation ε static pressure ψ 22.9 [76] static pressure mass flow P SHAFT 3.51…”

Comprehensive Review of Pump as Turbine

“…PAT covering different specific speeds was designed to explore the effects of blade thickness on the performance [25]. Numerical and experimental methodologies are applied.…”

“…From the fundamentals of energy transfer in turbines, the output mechanical shaft power and Euler turbine head can be represented by [25]:…”