scholarly journals MULTI-FACTOR HEAT EXCHANGER DESIGN MODELS

2021 ◽  
Vol 2 (37) ◽  
pp. 49-54
Author(s):  
R. Klimov ◽  
E. Lusta
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Regression Equations ◽  
Simple Formulation ◽  
Finned Tubes ◽  
Heat Exchanger Design ◽  
Exchange Area ◽  
Compactness Factor ◽  
Shell And Tube ◽  
Fisher’S Criterion

Compressed air is widely used in enterprises, and it is possible to reduce air consumption on pneumatic devices by heating. Most often, heating is carried out in shell-and-tube heat exchangers. To increase the area of heat exchange between the heating medium and the air, finned tubes are used, which can significantly reduce the volume occupied by the heater. The design of the heater is influenced by many factors, and the importance of the influence of each of them can differ significantly. It is advisable to use the overall characteristic in the form of a compactness factor, which shows the ratio of the heat exchange area to the volume of the heater. The work developed a method for determining the optimal design of heaters by such a parameter as the compactness factor. The obtained regression equations make it possible to determine the influence of such factors as the number of rows of tubes across the flow and the length of one tube on the volume occupied by the heat exchanger and the compactness factor. According to Fisher's criterion, the equations of the model are adequate to the true dependence with a confidence level of 95%. Most of all, the volume of the heat exchanger and the compactness are affected by the number of tubes transverse to the air flow. Changing the length of one tube does not fundamentally affect the obtained values of the output parameters. With an increase in the length of one tube and their number across the flow, it is possible to achieve the highest values of the compactness coefficient, the dependence of which on the main factors has a pronounced maximum. Using the developed technique, it is possible, in a fairly simple formulation, to analyze the value of the compactness factor for various combinations of the above factors and to optimize the design of the heater.

Shellside Waterflow Pressure Drop Distribution Measurements in an Industrial-Sized Test Heat Exchanger

1988 ◽  
Vol 110 (1) ◽  
pp. 60-67 ◽  
Author(s):  
H. Halle ◽  
J. M. Chenoweth ◽  
M. W. Wambsganss
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Operating Cost ◽  
Power Requirement ◽  
Pressure Drops ◽  
Pressure Losses ◽  
Finned Tubes ◽  
Heat Exchanger Design ◽  
Isothermal Water

Throughout the life of a heat exchanger, a significant part of the operating cost arises from pumping the heat transfer fluids through and past the tubes. The pumping power requirement is continuous and depends directly upon the magnitude of the pressure losses. Thus, in order to select an optimum heat exchanger design, it is is as important to be able to predict pressure drop accurately as it is to predict heat transfer. This paper presents experimental measurements of the shellside pressure drop for 24 different segmentally baffled bundle configurations in a 0.6-m (24-in.) diameter by 3.7-m (12-ft) long shell with single inlet and outlet nozzles. Both plain and finned tubes, nominally 19-mm (0.75-in.) outside diameter, were arranged on equilateral triangular, square, rotated triangular, and rotated square tube layouts with a tube pitch-to-diameter ratio of 1.25. Isothermal water tests for a range of Reynolds numbers from 7000 to 100,000 were run to measure overall as well as incremental pressure drops across sections of the exchanger. The experimental results are given and correlated with a pressure drop versus flowrate relationship.

Shell and tube heat exchanger design using mixed‐integer linear programming

AIChE Journal ◽  
2016 ◽  
Vol 63 (6) ◽  
pp. 1907-1922 ◽  
Author(s):  
Caroline de O. Gonçalves ◽  
André L. H. Costa ◽  
Miguel J. Bagajewicz
Keyword(s):  
Linear Programming ◽  
Heat Exchanger ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Mixed Integer ◽  
Tube Heat Exchanger ◽  
Heat Exchanger Design ◽  
Shell And Tube

Concurrent Reduction of Draft Height and Heat-Exchange Area for Large Dry Cooling Towers

1974 ◽  
Vol 96 (3) ◽  
pp. 279-285 ◽  
Author(s):  
F. K. Moore ◽  
T. Hsieh
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Full Description ◽  
Large Power ◽  
Water Pumping ◽  
Exchange Area ◽  
Fold Reduction ◽  
Water Side ◽  
Dry Cooling Tower ◽  
Dry Cooling

A procedure is outlined to meet simultaneous requirements to reduce overall size of a dry cooling tower for a large power plant, and to reduce the size (surface area) of the associated air-water heat exchanger. First, tower exit dimensions (or fan power) are specified as attainable fractions of their theoretical minima as found from a draft equation. Then a heat-exchanger type is chosen, having as small an air hydraulic diameter as feasible. Appropriate equations and assumptions dealing with air side and water side heat exchange and water pumping power then yield a full description of tower and heat-exchanger characteristics for a given tower duty. A specific example is worked out and compared with the tower at Rugeley, England. We find that a very open heat exchanger, of shallow depth (one in or less) results from our analysis, and in a proposed configuration of acceptable header loss gives a 1/3 height reduction and a four-fold reduction of heat-exchanger area.

A Numerical Algorithm and a Graphical Method to Size a Heat Exchanger

2011 ◽  
Author(s):  
Torsten Berning
Keyword(s):  
Heat Exchanger ◽  
Numerical Algorithm ◽  
Heat Exchangers ◽  
Graphical Method ◽  
Application Software ◽  
Microsoft Excel ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Heat Exchanger Design ◽  
Shell And Tube

This paper describes the development of a numerical algorithm and a graphical method that can be employed in order to determine the overall heat transfer coefficient inside heat exchangers. The method is based on an energy balance and utilizes the spreadsheet application software Microsoft Excel™. The application is demonstrated in an example for designing a single pass shell and tube heat exchanger that was developed in the Department of Materials Technology of the Norwegian University of Science and Technology (NTNU) where water vapor is superheated by a secondary oil cycle. This approach can be used to reduce the number of hardware iterations in heat exchanger design.

scholarly journals Numerical Simulation of The Effect of Baffle on Heat Transfer Performance of Shell-and-Tube Heat Exchanger

2021 ◽  
Vol 7 (1) ◽  
pp. 248-253
Author(s):  
Z. Guo ◽  
J. Shan ◽  
J. Li ◽  
Levtsev
Keyword(s):  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Pressure Field ◽  
Transverse Flow ◽  
Engineering Practice ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Exchange Area ◽  
Shell And Tube ◽  
Simulation Results

Baffle heat exchanger is widely used in various production activities because of its simple design and strong adaptability, so the structural optimization of baffle heat exchanger is of great significance to engineering practice. COMSOL software was used to simulate the shell-and-tube heat exchanger with baffles. By comparing and analyzing the simulation results, we find that the temperature field and pressure field of baffle plate are distributed evenly; The existence of baffles leads to the transverse flow of air, which increases the heat exchange area. Another advantage of using baffles is that vibration due to fluid flow can be reduced.

The Variation in Effectiveness of Low-Finned Tubes Within a Shell-and-Tube Heat Exchanger for Supercritical CO2

2012 ◽  
Author(s):  
Patrick M. Fourspring ◽  
Joseph P. Nehrbauer
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Exchanger ◽  
Thermal Conductance ◽  
Heat Transfer Area ◽  
Shell Side ◽  
Additional Heat ◽  
Tube Heat Exchanger ◽  
Finned Tubes ◽  
Shell And Tube

Low-finned tubes can be effective in baffled flow heat exchangers, if the heat transfer coefficients on either side of the heat exchanger differ greatly and therefore limit the thermal conductance of the heat exchanger. Low-finned tubes can increase thermal conductance by providing additional heat transfer area on the limiting side. The height and the spacing of the low-fins must be greater than the thickness of the thermal boundary layer on the low-finned side of the heat exchanger. Otherwise, the effectiveness of the additional area that the low-finned tubes provide will be reduced. The boundary layer thickness is dependent on the velocity and the thermophysical properties of the fluids. Therefore, in a standard shell-and-tube heat exchanger, the number of heat exchanger shell-side baffles needs to be properly considered to provide the correct shellside velocity without introducing too much pressure drop. Testing of a shell-and-tube heat exchanger containing low-finned tubes varied the flow rate and pressure of the supercritical CO2 on the shell side as water provided the cooling on the tube side. The testing maintained the temperature and pressure of the CO2 above the critical point in order to determine the changes in the effectiveness of the low-finned tubes and thus the heat transfer rate of the heat exchanger. The results show that the additional heat transfer area provided by the low-finned tubes will remain fully effective, even as the supercritical fluid nears its critical point or a pseudo-critical temperature. This result also supports (but is not sufficient to prove) the guidance to limit the estimated thickness of the thermal boundary layer to the fin height and twice the fin spacing to ensure the additional heat transfer area provided by the low-finned tubes remain effective.

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