Relation Between the Thermal Effectiveness of Overall Parallel and Counterflow Heat Exchanger Geometries

1989 ◽  
Vol 111 (2) ◽  
pp. 294-299 ◽  
Author(s):  
A. Pignotti
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Rate Ratio ◽  
Simple Relation ◽  
Two Fluids ◽  
The Heat Transfer Coefficient

A simple relation is established between the thermal effectiveness of two heat exchanger configurations that differ from each other in the inversion of either one of the two fluids. Using this relation, if the expression for the effectiveness of a configuration, as a function of the heat capacity rate ratio, and the number of heat transfer units, is known, the corresponding expression for the “inverse” configuration is immediately obtained. The relation is valid under the assumptions of temperature independence of the heat transfer coefficient and heat capacity rates, when one of the fluids proceeds through the exchanger in a single, mixed stream. The property is illustrated with several examples from the available literature.

Test and Analysis on the Heat Transfer Coefficient of the Mixed Plate Heat Exchanger

2014 ◽  
Vol 552 ◽  
pp. 55-60
Author(s):  
Zheng Ming Tong ◽  
Peng Hou ◽  
Gui Hua Qin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mixed Mode ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Fitting Method ◽  
Engineering Significance ◽  
The Heat Transfer Coefficient

In this article, we use BR0.3 type plate heat exchanger for experiment,and the heat transfer coefficient of the mixed plate heat exchanger is explored. Through the test platform of plate heat exchanger, a large number of experiments have been done in different mixed mode but the same passageway,and lots experimental data are obtained. By the linear fitting method and the analysis of the data, the main factors which influence the heat transfer coefficient of mixed plate heat exchanger were carried out,and the formula of heat transfer coefficient which fits at any mixed mode plate heat exchanger is obtained, to solve the problem of engineering calculation.The fact , there is no denying that the result which we get has great engineering significance

Thermal Effectiveness of Multiple Shell and Tube Pass TEMA E Heat Exchangers

1988 ◽  
Vol 110 (1) ◽  
pp. 54-59 ◽  
Author(s):  
A. Pignotti ◽  
P. I. Tamborenea
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Transfer Coefficient ◽  
Heat Exchangers ◽  
Rate Ratio ◽  
Algebraic Solution ◽  
Tube Heat Exchanger ◽  
Transverse Mixing ◽  
Shell And Tube ◽  
The Heat Transfer Coefficient

The thermal effectiveness of a TEMA E shell-and-tube heat exchanger, with one shell pass and an arbitrary number of tube passes, is determined under the usual symplifying assumptions of perfect transverse mixing of the shell fluid, no phase change, and temperature independence of the heat capacity rates and the heat transfer coefficient. A purely algebraic solution is obtained for the effectiveness as a function of the heat capacity rate ratio and the number of heat transfer units. The case with M shell passes and N tube passes is easily expressed in terms of the single-shell-pass case.

Experimental Study on Integrated Performance for Flower Baffle Heat Exchanger’s Distance between Two Flower Baffles

2010 ◽  
Vol 29-32 ◽  
pp. 132-137 ◽  
Author(s):  
Xue Jiang Lai ◽  
Rui Li ◽  
Yong Dai ◽  
Su Yi Huang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
The One ◽  
Integrated Performance ◽  
Quantity Of Heat ◽  
Side Flow ◽  
The Heat Transfer Coefficient

Flower baffle heat exchanger’s structure and design idea is introduced. Flower baffle heat exchanger has unique support structure. It can both enhance the efficiency of the heat transfer and reduce the pressure drop. Through the experimental study, under the same shell side flow, the heat transfer coefficient K which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. The heat transfer coefficient K which the distance between two flower baffles is 147mm is close to the one of which the distances between two flower baffles is 134mm. The shell volume flow V is higher, the incremental quantity of heat transfer coefficient K is more. The integrated performance K/Δp of flower baffle heat exchanger which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. Therefore, the best distance between two flower baffles exists between 134mm~147mm this experiment.

scholarly journals Studies on the Heat Transfer Coefficient and Pressure Drop of Several Kinds of Plate Heat Exchanger

1968 ◽  
Vol 32 (11) ◽  
pp. 1127-1132,a1 ◽  
Author(s):  
Katsuto Okada ◽  
Minobu Ono ◽  
Toshio Tomimum ◽  
Hirotaka Konno ◽  
Shigemori Ohtani
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
The Heat Transfer Coefficient

Study on Free Convection Heat Transfer in a Finned Tube Array

2015 ◽  
Vol 23 (01) ◽  
pp. 1550007 ◽  
Author(s):  
Ryoji Katsuki ◽  
Tsutomu Shioyama ◽  
Chikako Iwaki ◽  
Tadamichi Yanazawa
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Finned Tube ◽  
Average Heat Transfer Coefficient ◽  
Average Heat ◽  
Finned Tubes ◽  
Air Cooled Heat Exchanger ◽  
The Heat Transfer Coefficient

We have been developing a free convection air cooled heat exchanger without power supply to improve economic efficiency and mechanical reliability. However, this heat exchanger requires a larger installation area than the forced draft type air cooled heat exchanger since a large heating surface is needed to compensate for the small heat transfer by natural convection. Therefore, we have been investigating a heat exchanger consisting of an array of finned tubes and chimney to increase the heat transfer coefficient. Since the heat transfer characteristics of finned tube arrays have not been clarified, we conducted experiments with a finned tube array to determine the relation between the configuration of finned tubes and the heat transfer coefficient of a tube array. The results showed that the average heat transfer coefficient increased with pitch in the vertical direction, and became constant when the pitch was over five times the fin diameter. The average heat transfer coefficient was about 1.4 times higher than that of a single finned tube in free space. The ratio of the average heat transfer coefficient of the finned tube array with chimney to that of a single finned tube was found to be independent of the difference in temperature between the tube surface and air.

scholarly journals Parameters of the plain weave meshfor the nozzle of a regenerative heat exchanger

2021 ◽  
pp. 9-15
Author(s):  
Yaroslav Dvoinos ◽  
Pavlo Yevziutin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Hydraulic Resistance ◽  
Wire Mesh ◽  
Simulation Experiments ◽  
Regenerative Heat ◽  
Plain Weave ◽  
The Heat Transfer Coefficient

Regenerative heat exchangers have disadvantages such as low heat transfer coefficient from the nozzle to the gas and high hydraulic resistance due to the design of the nozzles. Wire-mesh nozzles can eliminate these shortcomings of regenerators. Wire-mesh nozzles have low hydraulic resistance and large heat transfer surface. The process of heat and mass transfer in a regenerative heat exchanger is considered. A series of numerical simulation experiments was performed. Theoretically, the optimal configuration of the nozzle was calculated: a plain weave mesh with a wire diameter of 0.4 mm, a weaving step of 2 mm, and a step of placing nets of 1 mm. The operational modes for the regenerator are considered, taking into account the period for drying the nozzle from moisture and the maximum mass of water that can hold the nozzle without the formation of drops. Given the condensation of moisture on the nozzle, the following assumptions are made: There is no temperature and concentration inhomogeneity in the cross section of the regenerator channel; The effect of thermal conductivity in the axial direction in contact between the nozzle elements on the temperature profile of the nozzle is insignificant; The time over which the regenerator is operated between the nozzle drying periods is quite short, and the thickness of the condensate layer does not affect the hydrodynamic mode of the heat regeneration process and the value of the heat transfer coefficient. The duration of the cooling and drying period depends on the humidity of the inlet air and the area of the nozzle. This is due to the need to prevent the accumulation of moisture in the device, which can lead to the reproduction of harmful bacteria and contamination of the nozzle. In the SolidWorks Flow Simulation application, simulation experiments were performed for a regenerator model accounting for the influence of compressed air motion resulting from grouped location of the nozzle elements, and the results are shown in the figures. Comparison of the results from analytical calculations and simulation experiments showed the efficiency of the mathematical model and the possibility of its use in the design calculation of regenerators. Correlation dependences have been established to determine the heat transfer coefficient and hydraulic resistance depending on the hydrodynamic conditions. The mathematical and physical model taking into account the condensation of moisture on the nozzle has been specified. Calculations have been performed for the optimal nozzle made in the form of a plain weave mesh with a wire diameter of 0.4 mm, a weaving step of 2 mm, and a step of placing nets of 1 mm.

scholarly journals Experimental Research and Simulation of Fin and Tube Heat Exchanger

2017 ◽  
Vol 9 (4) ◽  
pp. 451-461
Author(s):  
Artur Rubcov ◽  
Sabina Paulauskaitė ◽  
Violeta Misevičiūtė
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Ventilation System ◽  
Experimental Tests ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
The Heat Transfer Coefficient

The paper provides the results of experimental and theoretical test of a wavy fin and tube heat exchanger used to cool air in a ventilation system when the wavy fin of the heat exchanger is dry and wet. The experimental tests, performed in the range of 1000<Re<4500 of the Reynolds number applying LMTD-LMED methodology, determined the dependency of the heat transfer coefficient on the supplied air flow rate with the varying geometry of the heat exchanger (the number of tube rows, the distance between fins, the thickness of the fin and the diameter of the tube). The experimental tests were performed on 9 heat exchangers in heating and 6 heat exchangers in cooling mode. After processing the results of the experimental tests, empirical equation defining the characteristics of the heat transfer coefficient of all heat exchangers were derived. The maximum heat transfer coefficient deviation is 11.6 percent. The correction factor of the wet fin (Lewis number) depending on the number of Reynolds, which ranges from 0.75 to 1.1 also is determined. Maximum capacity deviation equals 3.7 percent. The obtained equations can only be applied to a certain group of heat exchangers (with the same shape of fins or the distance between the tubes). The results of the experimental test and simulation with ANSYS program are compared and the heat transfer coefficients vary from 6.5 to 11.4 percent.

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