A review on technology, configurations, and performance of cross‐flow hydrokinetic turbines

2019 ◽  
Author(s):  
Gaurav Saini ◽  
Rajeshwer Prasad Saini
Keyword(s):  
Cross Flow ◽  
Hydrokinetic Turbines ◽  
And Performance

Flow and Performance Characteristics of a Double-Blade Hydrofoil

2012 ◽  
Vol 433-440 ◽  
pp. 7218-7222 ◽  
Author(s):  
Tahir Yavuza ◽  
Birol Kilkis ◽  
Emre Koc ◽  
Ozgur Erol
Keyword(s):  
Wind Power ◽  
Fossil Fuels ◽  
Clean Energy ◽  
Performance Characteristics ◽  
Energy Resources ◽  
Environmental Crisis ◽  
Operational Effectiveness ◽  
Hydrokinetic Turbines ◽  
The World ◽  
And Performance

While our planet is rapidly approaching an environmental crisis under the dominant use of depleting fossil fuels, the need for exploiting all forms of new, small carbon foot-print, renewable, and clean energy resources are increasing in the same proportion. Therefore, the need for exploring all types of clean energy resources that the world has- some of which might have not attracted sufficient attention before- is essential in order to implement sufficient, efficient, and widely use all them. In this respect, operational effectiveness of the wind and hydrokinetic turbines depend on the performance of the airfoils chosen. Using double-blade airfoils in the wind and hydrokinetic turbines, minimum wind and hydrokinetic flow velocities to produce meaningful and practical mechanical power reduces to 3- 4 m /s for wind turbines and 1-1.5 m/s or less for hydrokinetic turbines. Consequently, double-blade hydrofoils may re-define the potentials of wind power and hydrokinetic power of the countries in positive manner.

Analytical Modeling and Performance Study of a Cross Flow Air Dehumidifier Using Liquid Desiccant

2014 ◽  
Vol 875-877 ◽  
pp. 1205-1213 ◽  
Author(s):  
Mohamed M. Bassuoni
Keyword(s):  
Numerical Solutions ◽  
Removal Rate ◽  
Cross Flow ◽  
Operating Conditions ◽  
Maximum Deviation ◽  
Performance Study ◽  
Liquid Desiccant ◽  
Mass Transfer Processes ◽  
And Performance ◽  
Air Conditioning Systems

The dehumidifier is a key component in liquid desiccant air conditioning systems. Various mathematical models of heat and mass transfer processes inside the dehumidifier are introduced and numerically solved in the literature. Analytical solutions have more advantages than numerical solutions in studying the dehumidifier performance parameters. This paper presents the results from an analytical model for the performance of an adiabatic cross flow liquid desiccant air dehumidifier. Calcium chloride is used as desiccant material in this investigation. Both humidity and temperature effectiveness of the dehumidifier are used to predict the performance of the device under various operating conditions. Good accuracy has been found between analytical solution and reliable experimental results with a maximum deviation of +6.63% and -5.65% in the moisture removal rate. The method developed here can be used in the quick prediction of the dehumidifier performance. The exit parameters from the dehumidifier are evaluated under the effects of variables such as air temperature and humidity, desiccant temperature and concentration and air to desiccant flow rates. The results show that hot humid air and desiccant concentration have the greatest impact on the performance of the dehumidifier.

scholarly journals Experimental Investigation of Helical Cross-Flow Axis Hydrokinetic Turbines, Including Effects of Waves and Turbulence

2011 ◽  
Author(s):  
Peter Bachant ◽  
Martin Wosnik
Keyword(s):  
Cross Flow ◽  
Surface Flow ◽  
Frame Rate ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Grid Turbulence ◽  
Flow Axis ◽  
Power Extraction ◽  
Tip Speed Ratio ◽  
Hydrokinetic Turbines

The performance characteristics of two cross-flow axis hydrokinetic turbines were evaluated in UNH’s tow and wave tank. A 1m diameter, 1.25m (nominal) height three-bladed Gorlov Helical Turbine (GHT) and a 1m diameter, four-bladed spherical-helical turbine (LST), both manufactured by Lucid Energy Technologies, LLP were tested at tow speeds up to 1.5 m/s. Relationships between tip speed ratio, solidity, power coefficient (Cp), kinetic exergy efficiency, and overall streamwise drag coefficient (Cd) are explored. As expected, the spherical-helical turbine is less effective at converting available kinetic energy in a relatively low blockage, free-surface flow. The GHT was then towed in waves to investigate the effects of a periodically unsteady inflow, and an increase in performance was observed along with an increase in minimum tip speed ratio at which power can be extracted. Regarding effects of turbulence, it was previously documented that an increase in free-stream homogenous isotropic turbulence increased static stall angles for airfoils. This phenomenon was first qualitatively investigated on a smaller scale with a NACA0012 hydrofoil in a UNH water tunnel, using an upstream grid turbulence generator and using high frame-rate PIV to measure the flow field. Since the angle of attack for a cross-flow axis turbine blade oscillates with higher amplitude as tip speed ratio decreases, any delay of stall should allow power extraction at lower tip speed ratios. This hypothesis was tested experimentally on a larger scale in the tow tank by creating grid turbulence upstream of the turbine. It is shown that the range of operable tip speed ratios is slightly expanded, with a possible improvement of power coefficient at lower tip speed ratios. Drag coefficients at higher tip speed ratios seem to increase more rapidly than in the non-turbulent case.

Numerical analysis and performance enhancement of a cross-flow hydro turbine

2015 ◽  
Vol 80 ◽  
pp. 819-826 ◽  
Author(s):  
Nirmal Acharya ◽  
Chang-Gu Kim ◽  
Bhola Thapa ◽  
Young-Ho Lee
Keyword(s):  
Numerical Analysis ◽  
Performance Enhancement ◽  
Cross Flow ◽  
Hydro Turbine ◽  
And Performance

Design of a Solar Tunnel Dryer Combined Heat with a Parabolic Trough for Paddy Drying

2016 ◽  
Vol 851 ◽  
pp. 239-243 ◽  
Author(s):  
Krissadang Sookramoon
Keyword(s):  
Heat Exchanger ◽  
Performance Test ◽  
Focal Point ◽  
Tracking System ◽  
Cross Flow ◽  
Hot Water ◽  
Parabolic Trough ◽  
Tunnel Dryer ◽  
And Performance ◽  
Flat Plate Collector

This paper presents the design, build and performance test of a solar tunnel dryer combined heat with a parabolic trough for paddy drying. A 2.27 m² parabolic trough stainless steel made with a single-axis solar tracking system produced hot water and delivered to the cross flow heat exchanger equipped with a solar tunnel dryer with the size of flat plate collector of 2.112 m2. The system received solar radiation and reflected sunlight to the receiver at the focal point of a parabolic trough. At this point, a copper heat pipe with the inside diameter of 25.4 mm for water heating is placed. A parabolic trough is covered with plastic sheets for protecting the wind in order to prevent the heat loss by convection. The produced hot water is used to warm the air and is sent to the heat exchanger and the blower passes hot air through the drying chamber of solar tunnel to dry paddy. The average drying temperature was 57.73 °C. The paddy moisture content was assessed in a reduction from 49.96 to 15.61 MC (% d.b.) in 6 hours. The heated air was around 245.87 W, with the incoming heat in the solar tunnel dryer of 1271.84 W. The thermal efficiency of a solar tunnel dryer, a parabolic trough, and the overall efficiency were on the average of 28.31%, 8.73%, and 3.80%, respectively.

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