Chemically Etched Cryogenic Micro Structure Heat Exchanger

2005 ◽  
Author(s):  
Jeheon Jung ◽  
Sangkwon Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Performance Test ◽  
Pulse Tube ◽  
Micro Structure ◽  
Counter Flow ◽  
Pulse Tube Refrigerator ◽  
Micro Channels ◽  
Flow Heat ◽  
Transfer Structure

A tandem 4 K pulse tube refrigerator requires a recuperator to be fully accomplished. The recuperator should be a counter-flow heat exchanger which has micro heat-transfer structure like a regenerator of cryogenic refrigerators. However, the technology of such a heat exchanger is not well established yet. Hence, the development of a counter-flow compact heat exchanger with micro structure is demanded first in order to proceed to the recuperative 4 K pulse tube refrigerator. This paper describes the design, fabrication and preliminary performance test of such a heat exchanger. The stainless steel micro structure with approximately 0.1 mm characteristic length has been created by chemical etching. The parallel V-shape double-sided micro channels (chevron stucture) in the heat exchanger enable the flow to be three-dimensionally well mixed so that the heat transfer at low Reynolds number can be enhanced. The etched plates are stacked and bonded through a vacuum brazing process to compose a plate-type heat exchanger. The chemically etched micro-structure heat exchanger has thermal effectiveness of 97%.

scholarly journals Investigation on fluid flow heat transfer and frictional properties of Al2O3 nanofluids used in shell and tube heat exchanger

2020 ◽  
Author(s):  
sreejesh S R chandran ◽  
Debabrata Barik ◽  
ANSALAM RAJ T G ◽  
Reby ROY
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transfer Rate ◽  
Working Fluid ◽  
Flow Properties ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Frictional Properties ◽  
Flow Heat ◽  
Shell And Tube

Abstract Nanofluids are generally utilized in providing cooling, lubrication phenomenon, controlling the thermophysical properties of the working fluid. In this work, nanoparticles of Al2O3 are added to the base fluid which flows through the counter flow arrangement in a turbulent flow condition. The hot and cold fluids used are ethylbenzene and water respectively and have different velocities on both shell and tube side. This study emphasizes the analysis of flow properties, friction loss, and energy transfer in terms of heat using nanofluid in the heat exchanger. The heat transfer rate of present investigation with nanoparticle addition is 4.63% higher in comparision to Dittus Boelter correlation. Apart from this, the obtained friction factor is 0.0376 very much closer to Gnielinski and Blasius correlations. This investigation proved that appropriate nanoparticle additions and baffle inclinations have fabulous impact upon the performance of heat exchanger and its effectiveness.

scholarly journals Optimization procedure of a new type counter–flow heat exchanger

2021 ◽  
Vol 2116 (1) ◽  
pp. 012093
Author(s):  
R Karvinen
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Procedure ◽  
Multi Objective Optimization ◽  
Counter Flow ◽  
Overall Heat Transfer Coefficient ◽  
Different Types ◽  
New Type ◽  
Flow Heat

Abstract Plenty of studies exist in books and archival journals dealing with different types of heat exchangers. In the paper an analytical approach to evaluate the overall heat transfer coefficient of a new type heat exchanger is presented. Derived equations are applied to multi-objective optimization of a very large economizer of a recovery boiler, when the exchanger mass and size should be small but simultaneously heat transfer rate high.

Flow Prediction and Conjugate Heat-Transfer Analysis of a Counter Flow Heat-Exchanger with Protruded Fin

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Manikandan Mohan ◽  
K.C. Udaiyakumar
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Conjugate Heat Transfer ◽  
Flow Analysis ◽  
Heat Transfer Analysis ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Flow Heat ◽  
Optimized Model ◽  
Cfd Method

Voluminous cram has been carried out in this project which is intended to improve the conjugate heat-transfer performance of a heat-exchanger. In this study, CFD method is effectively used to predict the effect of Protruded Fins in heat exchanger, which protrudes inside the tube in addition to the shell side. CFD analysis on Protruded Finned Heat Exchanger (PFHE) is carried out with three different fin configurations like rectangular, triangular and parabolic fins. The baseline model of counter flow shell-tube heat-exchanger is considered with standard dimensions and analyzed initially without fins. Later the numbers of fins are increased to optimize the fin position and counts. The shape of the fins is then modified to find an optimized model with a higher heat-transfer coefficient. Hence, the present conjugate heat-transfer and flow analysis focus on optimizing the number of fins for a heat-exchanger with counter flow along with the shape optimization of fins. The computational values are measured with the net heat exchange between the cold and hot-fluids in terms of temperature difference. Also, the area averaged surface heat transfer co-efficient (h) of the heat exchanger with different fin configurations are plotted and compared.

Differential Methods for the Performance Prediction of Multistream Plate-Fin Heat Exchangers

1992 ◽  
Vol 114 (1) ◽  
pp. 41-49 ◽  
Author(s):  
B. S. V. Prasad ◽  
S. M. K. A. Gurukul
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Performance Prediction ◽  
Heat Exchangers ◽  
Loss Functions ◽  
Computer Algorithms ◽  
Counter Flow ◽  
Flow Heat ◽  
Differential Methods ◽  
Section Level

Use of traditional methods of rating can prove inaccurate or inadequate for many plate-fin heat exchanger applications. The superiority in practical situations of differential methods, based on dividing the heat exchanger into several sections and a step-wise integration of the heat transfer and pressure loss functions, is discussed. Differential methods are developed for counterflow, crossflow, and cross-counter-flow heat exchangers. The methods developed also avoid iterations at the section level calculations. Design of computer algorithms based on these methods is outlined. Two computer programs developed using the methods are presented and the results for a few typical cases are discussed.

Thermal Efficiency of the Cross Flow Heat Exchangers

2006 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Cross Flow ◽  
Algebraic Expression ◽  
Counter Flow ◽  
Optimum Heat ◽  
Flow Heat

The heat exchanger efficiency is defined as the ratio of the actual heat transfer in a heat exchanger to the optimum heat transfer rate. The optimum heat transfer rate, qopt, is given by the product of UA and the Arithmetic Mean Temperature Difference, which is the difference between the average temperatures of hot and cold fluids. The actual rate of heat transfer in a heat exchanger is always less than this optimum value, which takes place in an ideal balanced counter flow heat exchanger. It has been shown that for parallel flow, counter flow, and shell and tube heat exchanger the efficiency is only a function of a single nondimensional parameter called Fin Analogy Number. The function defining the efficiency of these heat exchangers is identical to that of a constant area fin with an insulated tip. This paper presents exact expressions for the efficiencies of the different cross flow heat exchangers. It is shown that by generalizing the definition of Fa, very accurate results can be obtained by using the same algebraic expression, or a single algebraic expression can be used to assess the performance of a variety of commonly used heat exchangers.

The Shell and Tube Heat Exchanger Efficiency and Its Relation to Effectiveness

2003 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Optimum Heat ◽  
Flow Heat ◽  
Shell And Tube

The heat exchanger efficiency is defined as the ratio of the actual heat transfer in a heat exchanger to the optimum heat transfer rate. The optimum heat transfer rate, qopt, is given by the product of UA and the Arithmetic Mean Temperature Difference, which is the difference between the average temperatures of hot and cold fluids. The actual rate of heat transfer in a heat exchanger is always less than this optimum value, which takes place in a balanced counter flow heat exchanger. It is shown that for parallel flow, counter flow, and shell and tube heat exchanger the efficiency is only a function of a single nondimensional parameter called Fin Analogy Number. Remarkably, the functional dependence of the efficiency of these heat exchangers on this parameter is identical to that of a constant area fin with an insulated tip. Also a general algebraic expression as well as a generalized chart is presented for the determination of the efficiency of shell and tube heat exchangers with any number of shells and even number of tube passes per shell, when the Number of Transfer Units (NTU) and the capacity ratio are known. Although this general expression is a function of the number of shells and another nondimensional group, it turns out to be almost independent of the number of shells over a wide range of practical interest. The same general expression is also applicable to parallel and counter flow heat exchangers.

Numerical Simulation of Heat Transfer to TiO2-Water Nanofluid Flow in a Double-Tube Counter Flow Heat Exchanger

2015 ◽  
pp. 413-422
Author(s):  
C. S. Oon ◽  
H. Nordin ◽  
A. Al-Shamma’a ◽  
S. N. Kazi ◽  
A. Badarudin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Counter Flow ◽  
Nanofluid Flow ◽  
Flow Heat
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