Augmentation of Heat Transfer and Pressure Drop Characteristics Inside a Double Pipe U-Tube Heat Exchanger by Using Twisted Tape Inserts

This paper investigates the convective heat transfer in a heat exchanger equipped with twisted tape elements to examine effects of the twisted tape truncation percentage, pitch value, position and Reynolds number using 3D numerical simulation. A symmetric heat flux is applied around the tube as the studied heat exchanger. Based on the influences in both heat transfer enhancement and pressure drop, the performance evaluation criterion (PEC) is utilized. Inserting twisted tape elements and reducing the pitch value significantly augment the Nusselt number, friction coefficient and PEC number compared to the plain tube. For the best case with a Reynolds number of 1000, the average Nusselt number increases by almost 151%, which is the case of fully fitted twisted tape at a pitch value of L/4. Moreover, increasing the twisted tape truncation percentage reduces both heat transfer and pressure drop. Furthermore, the highest heat transfer rate is achieved when the truncated twisted tape is located at the entrance of the tube. Finally, it is concluded that for P = L, L/2, L/3 and L/4, the optimum cases from the viewpoint of energy conservation are twisted tapes with truncation percentages of 75, 50, 50 and 0%, in which the related PEC numbers at a Reynolds number of 1000 are almost equal to 1.08, 1.24, 1.4 and 1.76, respectively.

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NUMERICAL INVESTIGATION OF THE EFFECT OF BAFFLE ORIENTATION AND BAFFLE CUT ON HEAT TRANSFER AND PRESSURE DROP OF A SHELL AND TUBE HEAT EXCHANGER

Equipment ◽

10.1615/ihtc13.p18.230 ◽

2006 ◽

Cited By ~ 1

Author(s):

K. Mohammadi ◽

H. Muller-Steinhagen ◽

W. Heidemann

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Pressure Drop ◽

Numerical Investigation ◽

Tube Heat Exchanger ◽

Shell And Tube

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Numerical simulation of the effect of baffle cut and baffle spacing on shell side heat exchanger performance using CFD

Chemical Product and Process Modeling ◽

10.1515/cppm-2020-0033 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Swanand Gaikwad ◽

Ashish Parmar

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Heat Exchanger ◽

Pressure Drop ◽

Transfer Coefficient ◽

Numerical Results ◽

Shell Side ◽

Tube Heat Exchanger ◽

Shell And Tube ◽

Two Parameters

AbstractHeat exchangers possess a significant role in energy transmission and energy generation in most industries. In this work, a three-dimensional simulation has been carried out of a shell and tube heat exchanger (STHX) consisting of segmental baffles. The investigation involves using the commercial code of ANSYS CFX, which incorporates the modeling, meshing, and usage of the Finite Element Method to yield numerical results. Much work is available in the literature regarding the effect of baffle cut and baffle spacing as two different entities, but some uncertainty pertains when we discuss the combination of these two parameters. This study aims to find an appropriate mix of baffle cut and baffle spacing for the efficient functioning of a shell and tube heat exchanger. Two parameters are tested: the baffle cuts at 30, 35, 40% of the shell-inside diameter, and the baffle spacing’s to fit 6,8,10 baffles within the heat exchanger. The numerical results showed the role of the studied parameters on the shell side heat transfer coefficient and the pressure drop in the shell and tube heat exchanger. The investigation shows an increase in the shell side heat transfer coefficient of 13.13% when going from 6 to 8 baffle configuration and a 23.10% acclivity for the change of six baffles to 10, for a specific baffle cut. Evidence also shows a rise in the pressure drop with an increase in the baffle spacing from the ranges of 44–46.79%, which can be controlled by managing the baffle cut provided.

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Experimental study of heat transfer and friction factor in a double pipe heat exchanger using twisted tape with dimple inserts

Energy Sources Part A Recovery Utilization and Environmental Effects ◽

10.1080/15567036.2021.1927248 ◽

2021 ◽

pp. 1-30

Author(s):

Sanjay Kumar Singh ◽

Arvind Kumar

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Heat Exchanger ◽

Friction Factor ◽

Twisted Tape ◽

Double Pipe ◽

Pipe Heat

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Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Nanomaterials ◽

10.3390/nano10091656 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1656 ◽

Cited By ~ 1

Author(s):

Mehdi Ghalambaz ◽

Hossein Arasteh ◽

Ramin Mashayekhi ◽

Amir Keshmiri ◽

Pouyan Talebizadehsardari ◽

...

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Performance Evaluation ◽

Heat Exchanger ◽

Evaluation Criterion ◽

Twisted Tape ◽

Performance Evaluation Criterion ◽

Twisted Tapes ◽

Double Pipe ◽

Pipe Heat

This study investigated the laminar convective heat transfer and fluid flow of Al2O3 nanofluid in a counter flow double-pipe heat exchanger equipped with overlapped twisted tape inserts in both inner and outer tubes. Two models of the same (co-swirling twisted tapes) and opposite (counter-swirling twisted tapes) angular directions for the stationary twisted tapes were considered. The computational fluid dynamic simulations were conducted through varying the design parameters, including the angular direction of twisted tape inserts, nanofluid volume concentration, and Reynolds number. It was found that inserting the overlapped twisted tapes in the heat exchanger significantly increases the thermal performance as well as the friction factor compared with the plain heat exchanger. The results indicate that models of co-swirling twisted tapes and counter-swirling twisted tapes increase the average Nusselt number by almost 35.2–66.2% and 42.1–68.7% over the Reynolds number ranging 250–1000, respectively. To assess the interplay between heat transfer enhancement and pressure loss penalty, the dimensionless number of performance evaluation criterion was calculated for all the captured configurations. Ultimately, the highest value of performance evaluation criterion is equal to 1.40 and 1.26 at inner and outer tubes at the Reynolds number of 1000 and the volume fraction of 3% in the case of counter-swirling twisted tapes model.

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