Experimental Study of Mixed Convection Shell-and-Coil Heat Exchanger

2008 ◽  
Author(s):  
Nasser Ghorbani Mianroudi ◽  
Mofid Gorji ◽  
Hessam Taherian
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Mixed Convection ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Equivalent Diameter ◽  
Coil Diameter ◽  
Laminar And Turbulent Flow ◽  
Helical Coils ◽  
Coil Heat Exchanger

In this study the mixed convection heat transfer in a coil-in-shell heat exchanger for various Reynolds numbers, various tube-to-coil diameter ratios and different dimensionless coil pitch was experimentally investigated. The experiments were conducted for both laminar and turbulent flow inside coil. Effects of coil pitch and tube diameters on shell-side heat transfer coefficient of the heat exchanger were studied. Different characteristic lengths were used in various Nusselt number calculations to determine which length best fits the data and several equations were proposed. The particular difference in this study in comparison with the other similar studies was the boundary conditions for the helical coils. The results indicate that the equivalent diameter of shell is the best characteristic length.

Effects of Baffle Width on Heat Transfer to an Immersed Coil Heat Exchanger: Experimental Optimization

2019 ◽  
Author(s):  
Julia Haltiwanger Nicodemus ◽  
Xiaoqi Huang ◽  
Emily Dentinger ◽  
Kyle Petitt ◽  
Joshua H. Smith
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Convection Heat Transfer ◽  
Hot Water ◽  
Outlet Temperature ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Water Storage Tank ◽  
Coil Heat Exchanger

Abstract In this work, we investigate the effects of the width of an annular baffle region on natural convection heat transfer to an immersed, coiled heat exchanger in an otherwise quiescent sensible hot water storage tank. In experiments, the coiled heat exchanger sits in an annular region created by the tank wall and a straight, cylindrical baffle. The width of this baffle region is 1.5, 2, 3, or 4 times the heat exchanger diameter, These experiments are compared to each other and to corresponding control experiments with no baffle. In general, all baffles create considerable benefits over their respective control experiments, consistent with past studies. The considered metrics of heat transfer rate, fraction of energy discharged from the tank, and heat exchanger outlet temperature show that heat transfer is improved slightly by narrowing the baffle region. For example, relative to their respective controls, the energy extracted from the tank after 30 min of discharge in the 1.5D, 2D, 3D and 4D experiments is 23.2%, 20.8%, 18.1%, and 14.7% higher, respectively. This improvement in natural convection heat transfer as the baffle region narrows is attributed to the increasing thermal stratification observed in experiments with increasingly narrow baffle regions.

Heat Transfer and Flow Characteristics of Liquid Nitrogen Laminar Fulling Films in Cryogenic Heat Transfer

2011 ◽  
Vol 148-149 ◽  
pp. 1514-1518
Author(s):  
Zhi Li ◽  
Zhong Min Li ◽  
Jun Guo
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Liquid Nitrogen ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Heat Transfer Efficiency ◽  
Improve Heat Transfer ◽  
The Impact ◽  
Film Flows

This paper studies the characteristics of both the dynamic heat and mass transfer of liquid nitrogen thin film which have vital significance to improve heat transfer efficiency and optimize the cryogenic heat exchanger. Liquid nitrogen laminar film flows in the brazed cryogenic heat exchanger with 2.3mm distance between plates. Relationship between the dimensionless thickness and the coefficient of heat convection of liquid nitrogen film is derived. And the impact of rate of vapor content, intensity of interfacial convection heat transfer and Reynolds numbers are calculated and analyzed.

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