scholarly journals Experimental tests of the effect of rotor diameter ratio and blade number to the cross-flow wind turbine performance

2018 ◽  
Author(s):  
Sandi Susanto ◽  
Dominicus Danardono Dwi Prija Tjahjana ◽  
Budi Santoso
Keyword(s):  
Wind Turbine ◽  
Cross Flow ◽  
Experimental Tests ◽  
Diameter Ratio ◽  
Blade Number ◽  
Turbine Performance ◽  
The Cross

Study on Performance and Flow Condition of a Cross-Flow Wind Turbine With a Symmetrical Casing

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Junichiro Fukutomi ◽  
Toru Shigemitsu ◽  
Hiroki Daito
Keyword(s):  
Wind Turbine ◽  
Rotational Speed ◽  
Flow Condition ◽  
Cross Flow ◽  
Low Noise ◽  
Maximum Power ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
The Cross

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10%) as compared to that of other small wind turbines. Prevailing winds in two directions often blow in urban and coastal regions. Therefore, in order to improve the performance and the flow condition of the cross-flow rotor, a casing suitable for this sort of prevailing wind conditions is designed in this research and the effect of the casing is investigated by experimental and numerical analysis. In the experiment, a wind tunnel with a square discharge is used and main flow velocity is set as 20 m/s. A torque meter, a rotational speed pickup, and a motor are assembled with the same axis as the test wind turbine and the tip speed ratio is changeable by a rotational speed controller. The casing is set around the cross-flow rotor and flow distribution at the rotor inlet and the outlet is measured by a one-hole pitot tube. The maximum power coefficient is obtained as Cpmax = 0.19 with the casing, however Cpmax = 0.098 without the casing. It is clear that the inlet and the outlet flow condition is improved by the casing. In the present paper, in order to improve the performance of a cross-flow wind turbine, a symmetrical casing suitable for prevailing winds in two directions is proposed. Then, the performance and the internal flow condition of the cross-flow wind turbine with the casing are clarified. Furthermore, the influence of the symmetrical casing on performance is discussed and the relation between the flow condition and performance is considered.

scholarly journals Conjugate Heat Transfer CFD Predictions of Impingement Jet Array Flat Wall Cooling Aerodynamics With Single Sided Flow Exit

2013 ◽  
Author(s):  
Abubakar M. El-Jummah ◽  
Gordon E. Andrews ◽  
John E. J. Staggs
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Conjugate Heat Transfer ◽  
Cross Flow ◽  
Diameter Ratio ◽  
Significant Feature ◽  
Axial Distance ◽  
Impingement Jet ◽  
The Cross

Conjugate heat transfer CFD studies were undertaken on impingement square jet arrays with self induced crossflow in the impingement gap with a single sided exit. The aim was to understand the aerodynamic interactions that result in the deterioration of heat transfer with axial distance, whereas the addition of duct flow heat transfer would be expected to lead to an increase in heat transfer with axial distance. A square array of impingement holes was investigated for a common geometry investigated experimentally, pitch to diameter ratio X/D of 5 and impingement gap to diameter ratio Z/D of 3.3 for 11 rows of holes in the crossflow direction. A metal duct wall was used as the impingement surface with an applied heat flux of 100kW/m2, which for a gas turbine combustor cooling application operating at steady state with a temperature difference of ∼450K corresponds to a convective heat transfer coefficient of ∼200 W/m2K. A key feature of the predicted aerodynamics was recirculation in the plane of the impingement jets normal to the cross-flow, which produced heating of the impingement jet wall. This reverse flow jet was deflected by the cross flow which had its peak velocity in the plane between the high velocity impingement jets. The cross-flow interaction with the impingement jets reduced the interaction between the jets on the surface, with lower surface turbulence as a result and this reduced the surface convective heat transfer. A significant feature of the predictions was the interaction of the cross-flow aerodynamics with the impingement jet wall and associated heat transfer to that wall. The results showed that the deterioration in heat transfer with axial distance was well predicted, together with predictions of the impingement wall surface temperature gradients.

scholarly journals Effect of Desiccant Solution Temperature on Regeneration Performance of a Cross-Flow Regenerator

2019 ◽  
Vol 111 ◽  
pp. 01086
Author(s):  
Hye-Won Dong ◽  
Hye-Jin Cho ◽  
Jae-Weon Jeong
Keyword(s):  
Aqueous Solution ◽  
Cross Flow ◽  
Optimal Solution ◽  
Experimental Tests ◽  
Coefficient Of Performance ◽  
Solution Temperature ◽  
Inlet Temperature ◽  
Humidity Ratio ◽  
Temperature And Humidity ◽  
The Cross

The purpose of this study is to investigate the effect of the inlet solution temperature on the performance of an adiabatic cross-flow regenerator using a lithium chloride (LiCl) aqueous solution, and to propose the optimal inlet solution temperature when operating this type of regenerator. In the experimental tests, the inlet solution temperature range varied from 50 to 90°C. The tests were carried out at 10°C intervals while the other conditions remained constant. The measurement parameters for the test were the inlet air dry-bulb temperature and humidity ratio, outlet air dry-bulb temperature and humidity ratio, air volume flow, solution density, and inlet and outlet solution temperatures. The regeneration effectiveness and coefficient of performance (COP) were selected to assess the heat and mass transfer performance of the cross-flow regenerator. The most important finding of this research was to determine the optimal solution inlet temperature in the cross-flow regenerator with the LiCl aqueous solution considering both the regenerator performance and energy consumption. The test results show that the recommended inlet solution temperature is 60°C, considering both regeneration effectiveness and COP.

Study on Performance and Internal Flow of Cross-Flow Wind Turbine

2003 ◽  
Author(s):  
Kazuki Takeuchi ◽  
Junichiro Fukutomi ◽  
Hidetoshi Kodani ◽  
Hironori Horiguchi
Keyword(s):  
Wind Turbine ◽  
Pressure Difference ◽  
Main Part ◽  
Cross Flow ◽  
Internal Flow ◽  
Power Coefficient ◽  
Construction Costs ◽  
Outer Flow ◽  
Output Coefficient ◽  
The Cross

The wind turbine has become more popular in recent years, but on the other hand, the developments of small wind-turbine have been legging behind. Because, the energy density of wind is small, since the efficiency of the main part of a wind turbine is very low. The construction costs become comparatively high-priced. Then, the main part of this subject is to show that, by collecting and sucking out more winds, a wind turbine is made to pass many winds and the new cross-flow wind turbine that increases an output coefficient is proposed. The cross-flow wind turbine has high torque and low speed characteristics and the structure are very simple. So, it can be used in a large wind velocity region. However, even if the power coefficient is high, it is about 10%. The purpose of this paper is to show how we can improve the power coefficient by applying a casing, which has a nozzle and a diffuser. This research was made to clear up fundamental characteristics of the interaction between outer flow and inner flow. Three kinds of cross-flow wind turbines were designed. The nozzle and diffuser have been designed suitable for the performance of wind turbine. The flow simulations by CFD have been carried out for various types of casings at 20 m/s with Fluent Ver5.0. All Wind tunnel experiments were performed at 20m/s. The case of casing 2, which have plate arranged near the separation point of cylinder, also experimented. The rotor that is settled in the casing 1 shows a larger power coefficient than the case without a casing. The casing of the cross-flow turbine makes a pressure difference between inflow and outflow. The pressure difference increases the mass flow rate. Therefore much more wind passes through into the cross-flow turbine. In this experiment, the power coefficient increased 1.5 times in the case with casing. A still higher output coefficient could be obtained in the case where it is shown by the casing 2.

An Experimental Investigation of Cross-Flow Turbine Efficiency

1994 ◽  
Vol 116 (3) ◽  
pp. 545-550 ◽  
Author(s):  
Venkappayya R. Desai ◽  
Nadim M. Aziz
Keyword(s):  
Experimental Investigation ◽  
Angle Of Attack ◽  
Cross Flow ◽  
Water Entry ◽  
Diameter Ratio ◽  
Geometric Parameters ◽  
Maximum Efficiency ◽  
Outer Diameter ◽  
Turbine Efficiency ◽  
The Cross

An experimental investigation was conducted to study the effect of some geometric parameters on the efficiency of the cross-flow turbine. Turbine models were constructed with three different numbers of blades, three different angles of water entry to the runner, and three different inner-to-outer diameter ratios. Nozzles were also constructed for the experiments to match the three different angles of water entry to the runner. A total of 27 runners were tested with the three nozzles. The results of the experiments clearly indicated that efficiency increased with increase in the number of blades. Moreover, it was determined that an increase in the angle of attack beyond 24 deg does not improve the maximum turbine efficiency. In addition, as a result of these experiments, it was determined that for a 24 deg angle of attack 0.68 was the most efficient inner-to-outer diameter ratio, whereas for higher angles of attack the maximum efficiency decreases with an increase in the diameter ratio from 0.60 to 0.75.

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