Numerical Analyses of a Straight Bladed Vertical Axis Darrieus Wind Turbine: Verification of DMS Algorithm and Qblade Code

Abstract

Wind energy is among the most cost-effective renewable energies. Till date, turbines with different configurations had been designed to harness wind power, each having unique superiorities. Darrieus turbines are one of the mostly investigated vertical axis wind turbines using either experimental or numerical methods. Experimental analyses are time consuming works which requires high amount of effort and expenses. Thus, computational fluid dynamics (CFD) methods have been commonly used by scientists and engineers in order of obtaining detailed performance and illustration of the fluid flow. Contrary to the horizontal axis machines, Darrieus turbines are difficult to be analyzed by CFD algorithms due to high pressure and velocity variations which arise from extreme changes in the angle of attack beyond the stall condition at different azimuthal position of the blades. Therefore, more simplified numerical models are generated employing double multiple streamtube (DMS) theory together with additional improvements. QBlade is one of the mostly used numerical methods based on the lifting line free vortex wake method developed for calculating rotor aerodynamics. The main scope of this study is to design a straight bladed Darrieus turbine (D=1028 mm, H=1460 mm, N=3) and to verify the double multiple streamtube theory and QBlade algorithm with the experimental and computational works. Analysis results represented good agreement with the previous studies especially at lower TSR ranges. Compare to the experimental results, an overestimation in the power coefficient is obtained at low free stream speed and high TSR ranges after exceeding the peak point. Sensitivity of the model to the Re number variations have also been outlined.

Comparative analysis of vertical wind turbines

“…Ось ординат -коэффициент преобразования Cp, на оси абсцисс отношение скорости лопасти к скорости ветра [1]. Из представленного графика можно заметить, что ротор Савониуса является менее быстроходным чем ротор Дарье.…”

Determination of efficient configurations of vertical axis wind turbine using design of experiments

“…Marten et al 30 elaborated on the procedure for designing and analyzing the flow field around HAWT and VAWT. Muratoğlu and Sungur 31 performed numerical simulations to verify the DMS algorithm using the Q-Blade software. Clarke et al 36 applied DMS theory to perform aerodynamic analysis of VAWT.…”

“…The analysis was performed based on a DMS model using Q-Blade software. 22,[29][30][31][32] Recently, various researchers have used this software for the analysis of wind turbines. Okpue 33 performed an aerodynamic analysis of VAWT and HAWT by using DMS, cascade models, and experimental testing.…”

Performance Analysis Of Vertical Axis Wind Turbine Blades Using Double Multiple Stream Tube Process

“…Using DMS, numerical models can be created so that they are simpler than CFD algorithms, to analyse and simulate vertical turbine-axis type (Darrieus) blades. This method is one of the most important numerical methods for calculating the aerodynamics of a fully wind turbine [12][13]. Since small turbines have low performance for several reasons, most notably rotor size, these turbine blades can be improved by working to improve more than one of these blades, such as the S 1210 and S 1223.…”