M. Mohan Ram Surya

Bio: M. Mohan Ram Surya is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Turbine & Rotor (electric). The author has an hindex of 5, co-authored 7 publications receiving 55 citations.

Experimental and numerical investigation of novel Savonius wind turbine

Abstract: Savonius wind turbines have distinct advantages in terms of simplicity, low noise, and ease of manufacturing, yet they are not preferred for large-scale power generation due to their lower aerodyna...

On the self starting of darrieus turbine : An experimental investigation with secondary rotor

Abstract: Darrieus type vertical axis wind turbines are preferred for the small scale distributed power generation for their distinctive advantages, yet these lift based turbines suffers from poor self-starting capability. As a potential solution, a Dual rotor Darrieus Turbine (DD) with secondary rotor in addition to the primary rotor has been proposed to improve the self-starting characteristics and to enhance the low wind speed performance. The current study experimentally evaluates the proposed rotor with two set of blades as a possible means of achieving higher static torque and thus promoting self-starting capability. Albeit, the design parameters for the secondary rotor such as solidity, appropriate airfoil, secondary rotor diameter, secondary rotor offset with respect to primary rotor requires extensive optimization, the current preliminary study is focused on the feasibility check of the DD turbine. Power coefficient, dynamic and static torque coefficient are obtained through wind tunnel test and compared with Conventional Darrieus (CD) turbine (only with primary rotor). The results indicate the novel dual rotor do improve the self-starting capability at the expense of reduced power performance.

On the improvement of starting torque of darrieus wind turbine with trapped vortex airfoil

Abstract: The Darrieus wind turbines are simple in design with high power coefficient, yet they are poor performers in low wind speed regime. As a potential solution to improve the low wind speed performance, a notched airfoil (KF-N-21) was incorporated into straight bladed Darrieus rotor and experimentally compared with conventional NACA0021 rotor from the earlier study. The experimental results displays the superior performance of KF-N-21 in the low Reynolds number without degrading the performance at the high Reynolds number. This paper presents the computational validation of previous experimental investigation and to numerically explore the two dimensional unsteady flow field over the notched airfoil in comparioson with NACA 0021. A detailed flow characteristics are presented in terms of velocity and pressure distribution by capturing the vortex bubble formation. The simulation results shows a good agreement with the experimental data endorsing the performance of KF-N-21 airfoil for a wide range of Reynolds number.

Comparitive CFD analysis of darrieus wind turbine with NTU-20-V and NACA0018 airfoils

Abstract: The present work numerically explores the performance characteristics of Darrieus turbine with NTU-20-V and NACA 0018 airfoils. The NTU-20-V airfoil was carved out to enhance the fatigue life of the aluminium extruded blades by reinforcing with glass fiber material in standard shapes. The earlier studies by the authors include conceiving the airfoil profile through genetic algorithm optimization followed by experimental aerodynamic characterization in terms of lift and drag coefficients. The objective of the current study is to evaluate the performance of Darrieus rotor with NTU-20-V airfoil in terms of power coefficient and torque coefficient for different Reynolds number and compare it with standard NACA0018 airfoil from which the new airfoil was derived. The computational exploration is anticipated to shed light on the flow characteristics with respect to NACA 0018 airfoil.

Computational Optimization of Adaptive Hybrid Darrieus Turbine: Part 1

Abstract: Darrieus-type Vertical Axis Wind Turbines (VAWT) are promising for small scale decentralized power generation because of their unique advantages such as simple design, insensitive to wind direction, reliability, and ease of maintenance. Despite these positive aspects, poor self-starting capability and low efficiency in weak and unsteady winds deteriorate further development. Adaptive Hybrid Darrieus Turbine (AHDT) was proposed by the author in the past study as a potential solution to enhance low wind speed characteristics. The objective of the current research is to optimize the parameters of AHDT. AHDT integrates a dynamically varying Savonius rotor with a Darrieus rotor. A fully detailed 2D numerical study employing Reynold-Averaged Navier Stokes (RANS) is carried out to investigate the impact of the Darrieus rotor diameter (DR) on the Savonius rotor (DT) with regard to hybrid turbine performance. The power coefficient of the Darrieus rotor is evaluated when the Savonius rotor is in the closed condition (cylinder) of various diameters. The influence of Reynolds number (Re) on the torque coefficient is examined. Power loss of 58.3% and 25% is reported for DR/DT ratio of 1.5 and 2 respectively for AHDT with solidity 0.5 at 9 m/s. The flow interaction between the Savonius rotor in closed configuration reveals the formation of von Karman vortices that interact with Darrieus blades resulting in flow detachment. An optimum diametrical ratio (DR/DT) of 3 is found to yield the maximum power coefficient of the Darrieus rotor.

The international energy agency

Abstract: This chapter surveys the role of the IEA as a key component of the international energy security system. First, it gives an overview of the nature of the energy security challenges and the key governance regimes that have been set up historically to manage these challenges, including the IEA. Then, it elaborates on the specific roles taken up by the IEA in global energy governance, particularly in light of the dramatic changes that characterize the global energy security system. Finally, it gives a comparative overview of the three oil market interventions that the IEA has so far coordinated, before presenting the conclusions.