An Experimental Study of Heat Transfer During Forced Convection over a Rectangular Body

1980 ◽  
Vol 102 (1) ◽  
pp. 146-151 ◽  
Author(s):  
F. L. Test ◽  
R. C. Lessmann
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Experimental Investigation ◽  
Aspect Ratio ◽  
Surface Temperature ◽  
Stagnation Point ◽  
Temperature Heat ◽  
Transfer Behavior ◽  
Rectangular Body ◽  
Rectangular Model

An experimental investigation has been performed to determine the constant surface temperature heat transfer behavior on the upper surface of a rectangular model with a chord length of 20.3 cm (8 in.) and an aspect ratio of 6/1. Data were obtained for angles of attack from 0 to 50 deg and freestream velocities of 9.1, 15.2, and 21.3 m/s (30, 50 and 70 ft/s). Separation existed on a portion of the upper surface for angles between 0 and 20 deg with the flow being turbulent after reattachment. Above 30 deg the flow was always laminar with the stagnation point on the upper surface. The heat transfer results in the laminar case were strongly influenced by freestream disturbances.

Heat Transfer During Wind Flow over Rectangular Bodies in the Natural Environment

1981 ◽  
Vol 103 (2) ◽  
pp. 262-267 ◽  
Author(s):  
F. L. Test ◽  
R. C. Lessmann ◽  
A. Johary
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Wind Flow ◽  
Finite Width ◽  
Two Dimensional ◽  
Disturbance Intensity ◽  
Temperature Heat ◽  
Two Dimensional Flow ◽  
Transfer Behavior ◽  
Made In

An experimental investigation has been performed to determine the constant temperature heat transfer behavior on the upper surface of a rectangular plate with a chord length of 122 cm (48 in.), a width of 81.3 cm (32 in.) and a thickness aspect ratio of 6/1. Special side attachments were made in order to maintain approximately two-dimensional flow over the finite width body when exposed to varying wind directions. The angle of attack was 40 deg or greater. Quasi-local values of STRe were found to be 200 percent higher than wind tunnel values and 300 percent higher than analytical predictions. The disturbance intensity of the wind flow was in the range of 20 to 50 percent and is thought to be related to the increase in heat transfer since the flow over the plate was found to be laminar.

scholarly journals Experimental study of water cooling effect on heat transfer to increase output power of 180 watt peak photovoltaic module

2018 ◽  
Vol 67 ◽  
pp. 01009
Author(s):  
Arrad Ghani Safitra ◽  
Fifi Hesty Sholihah ◽  
Erik Tridianto ◽  
Ikhsan Baihaqi ◽  
Ni Nyoman Ayu Indah T.
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Surface Temperature ◽  
Output Power ◽  
Cooling Water ◽  
Photovoltaic Module ◽  
Water Cooling ◽  
Water Replacement ◽  
Pv Modules ◽  
Water Height

Photovoltaic (PV) modules require solar radiation to generate electricity. This study aims to determine the effect of water cooling PV modules on heat transfer, output power, and electrical efficiency of PV modules. The experiments carried out in this study were to vary the heights of flooded water (with and without cooling water replacement control) and cooling water flow. Variations in the height of flooded water are 0,5 cm, 1 cm, 2 cm, and 4 cm. While the flow rate variations are 2 L/min, 4 L/min, and 8 L/min. The flooded water replacement control will be active when the PV surface temperature reached 45°C. When the temperature dropped to 35°C, the cooler is disabled to let more photon to reach PV surface. The results showed that the lowest heat transfer occurred in the variation of 4 cm flooded water height without water replacement control, i.e. 28.53 Watt, with an average PV surface temperature of 32.92°C. The highest average electric efficiency occurred in the variation of 0,5 cm flooded water height with water replacement control, i.e. 13.12%. The use of cooling water replacement control is better due to being able to skip more photons reach PV surface with low PV temperature.

An Experimental Study of Convective Heat Transfer in Radially Rotating Rectangular Ducts

1991 ◽  
Vol 113 (3) ◽  
pp. 604-611 ◽  
Author(s):  
C. Y. Soong ◽  
S. T. Lin ◽  
G. J. Hwang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Reynolds Number ◽  
Aspect Ratio ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Rotational Speed ◽  
Main Flow ◽  
Buoyancy Flow ◽  
Aspect Ratios

The paper presents an experimental study of convective heat transfer in radially rotating isothermal rectangular ducts with various height and width aspect ratios. The convective heat transfer is affected by secondary flows resulting from Coriolis force and the buoyancy flow, which is in turn due to the centrifugal force in the duct. The growth and strength of the secondary flow depend on the rotational Reynolds number; the effect of the buoyancy flow is characterized by the rotational Rayleigh number. The aspect ratio of the duct may affect the secondary flow and the buoyancy flow, and therefore is also a critical parameter in the heat transfer mechanism. In the present work the effects of the main flow, the rotational speed, and the aspect ratio γ on heat transfer are subjects of major interest. Ducts of aspect ratios γ=5, 2, 1, 0.5, and 0.2 at rotational speed up to 3000 rpm are studied. The main flow Reynolds number ranges from 700 to 20,000 to cover the laminar, transitional, and turbulent flow regimes in the duct flow. Test data and discussion are presented.

The Effect of Free-Stream Turbulence on Heat Transfer From a Rectangular Prism

1984 ◽  
Vol 106 (2) ◽  
pp. 268-275 ◽  
Author(s):  
D. C. McCormick ◽  
F. L. Test ◽  
R. C. Lessmann
Keyword(s):  
Heat Transfer ◽  
Pressure Gradient ◽  
Transfer Rate ◽  
Free Stream ◽  
Two Dimensional ◽  
Free Stream Turbulence ◽  
Favorable Pressure Gradient ◽  
Temperature Heat ◽  
Predicted Values ◽  
Rectangular Body

This paper discussses the effect of free-stream turbulence on the constant temperature heat transfer rate from the surface of a two-dimensional rectangular body that is subject to a strongly favorable pressure gradient. Free-stream turbulence levels of 2 to 5 percent enhanced the heat transfer by 48 to 55 percent over predicted laminar values. Free-stream turbulence levels of 10 to 35 percent produced heat transfer results that behaved in some aspects as turbulent predictions, although considerably enhanced in magnitude over the predicted values.

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