Investigation of Heat Transfer in Straight and Curved Rectangular Ducts for Laminar and Transition Flows PDF Download
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Author: Robert George Holihan (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
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Book Description
An experimental investigation was conducted to examine convection heat transfer in a duct of rectangular cross-section, having both a straight and curved flow passage. One wall was kept at a constant temperature, with the opposite wall being adiabatic. Heating of the air flowing in the channel was accomplished through Joulean heating of a wall composed of Temsheet. The experiments were conducted for steady state in Laminar and Transition flows. Development and propagation of the Taylor-Gortler vortices was shown to enhance the heat transfer rate in the curved section as compared to the straight section. (Author).
Author: Robert George Holihan (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
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Book Description
An experimental investigation was conducted to examine convection heat transfer in a duct of rectangular cross-section, having both a straight and curved flow passage. One wall was kept at a constant temperature, with the opposite wall being adiabatic. Heating of the air flowing in the channel was accomplished through Joulean heating of a wall composed of Temsheet. The experiments were conducted for steady state in Laminar and Transition flows. Development and propagation of the Taylor-Gortler vortices was shown to enhance the heat transfer rate in the curved section as compared to the straight section. (Author).
Author: James Claude Ballard (III.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Book Description
Experimental investigations have been conducted to examine the general problem of convective heat transfer in a rectangular cross section channel with both straight and curved passages. The experimental configuration was modeled as infinite parallel plates with one wall at a constant heat flux and the opposite wall adiabatic. The air flow through the channel was heated through the Joulean heating of a wall composed of Temsheet. Liquid crystals applied to the surface of the Temsheet were used to confirm the presence of the Taylor-Gortler vortices. Average Nusselt number mesurements were used to investigate their effect on heat transfer from the curved test section. Experiments were conducted for steady state laminar flow that was hydrodynamically developed and thermally developing. It was confirmed that the Taylor-Gortler vortices enhanced the heat transfer process in the curved section. The experimental data was compared with several analytic studies with good results. (Author).
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
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Book Description
An experimental apparatus has been constructed and tested to examine the convective heat transfer in straight and curved ducts of rectangular cross-section. The channel can be configured with both walls independently heated at a constant heat flux, or one wall at a constant heat flux and the opposite wall adiabatic. Local and average Nusselt numbers can be calculated, and used to evaluate the effect of curvature on heat transfer. Experiments were conducted at steady state of turbulent flow with one wall heated at a constant flux and the opposite wall adiabatic. The heat transfer characteristics of the straight and curved sections, on both the inner and outer walls, were compared. The heat transfer rate of the concave curved wall proved to be enhanced over both the convex curved wall and both straight sections. Keywords: Taylor-Gortler Vortices, Dean Number, Heat Transfer, Turbulent Flow, Rectangular Curved Channel, Rectangular Straight Channel, Secondary Flow, Concave, and Convex.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
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Book Description
An experimental apparatus has been constructed and tested to examine the convective heat transfer in straight and curved ducts of rectangular cross-section. The channel can be configured with both walls independently heated at a constant heat flux, or one wall at a constant heat flux and the opposite wall adiabatic. Local and average Nusselt numbers can be calculated, and used to evaluate the effect of curvature on heat transfer. Experiments were conducted at steady state of turbulent flow with one wall heated at a constant flux and the opposite wall adiabatic. The heat transfer characteristics of the straight and curved sections, on both the inner and outer walls, were compared. The heat transfer rate of the concave curved wall proved to be enhanced over both the convex curved wall and both straight sections. Keywords: Taylor-Gortler Vortices, Dean Number, Heat Transfer, Turbulent Flow, Rectangular Curved Channel, Rectangular Straight Channel, Secondary Flow, Concave, and Convex.
Author: Joel L. Wilson
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 162
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Book Description
An experimental investigation has been conducted to examine the convective heat transfer in straight and curved ducts of rectangular cross section. The experimental configuration was modeled as infinite parallel plates with one wall at a constant heat flux and the opposite wall adiabatic. Experiments were conducted at steady state for turbulent flow using average Nusselt numbers to compare the heat transfer characteristics of the straight and curved sections. The development of Taylor-Gortler vortices in the curved section proved to enhance the heat transfer rate over that of the straight section. Improved heat exchanger and turbine blade design could both result from a better understanding of the effects of curvature on the rate of heat transfer. Originator-supplied keywords: Taylor-Gortler vortices, Heat transfer; Secondary flow; Rectangular curved channel; Rectangular straight channel; Temsheet; Joulean heating; and Turbulent flow.
Author: James Claude Ballard
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
A numerical study of heat transfer in 90°, constant cross-section curved duct, steady, laminar flow is presented. The work is aimed primarily at characterizing the effects of duct geometry on heat transfer by considering, especially, the role of secondary motions during the developing period of the flow. However, due consideration has also been given to varying initial conditions of velocity and temperature at the entrance section to the duct. In addition, an assessment is made of the relative contributions of individual duct walls to heat transfer in the flow. It is found that, in general, heat transfer increases with Dean number with the largest transfer rates occurring through the duct side walls and outer-curvature wall. Duct geometries with aspect ratio greater or smaller than unity have weaker secondary motions and are less effective for heat transfer. Similarly, plug-flow entrance profiles for velocity retard the development of cross-section flow thus inhibiting a significant contribution to heat transfer. It is concluded that short ducts with strong curvature and intense secondary motions can be as effective for heat transfer as longer ducts which are less strongly curved. Calcuations are based on fully elliptic (in space) forms of the transport equation governing the flow. They are of engineering value and are limited in accuracy only by the degree of computational mesh refinement. A comparison with calculations based on parabolic equations has been made and it is shown how the latter can lead to erroneous results for strongly curved flows.
Author:
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ISBN:
Category :
Languages : en
Pages : 0
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A rectangular cross section channel with both straight and curved test sections was used to investigate the effect of Taylor-Goertler vortices on the heat transfer from the curved section by comparing the results with those obtained in the straight section. The flow was heated through the Joulean heating of one of the walls which was made of Temsheet. Liquid crystals were applied on the surfaces of both test sections. Experiments were run for several values of the volumetric flow rate corresponding to Reynolds numbers between 258 and 920. The average Nusselt number was calculated for each experiment and plotted as function of the Reynolds and Dean numbers. Three distinct regions of the average Nusselt number were observed in the curved section when compared with the straight section. The presence of Taylor-Goertler vortices in the curved section was verified from the distribution of the liquid crystal color bands. It was concluded that the overall effect of the vortices whenever they occurred was to improve the heat transfer process from the curved section. (Author).
Author: Henry M. Cheng
Publisher:
ISBN:
Category :
Languages : en
Pages : 80
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Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836
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