Numerical Study of Heat Transfer Enhancement of Turbulent Flow Using Twisted Tape Insert Fitted with Hemispherical Extruded Surface

Rubbi, Fazlay; Habib, Khairul; Tusar, Mehedi; Das, Likhan; Rahman, Tauhidur

doi:10.18280/ijht.380205

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…The authors showed that the shell-side heat transfer coefficient increases from 9.3 to 25.5%, and the pressure drop is reduced from 15.3 to 47.1% compared to using a segmental baffle. Fazlay et al [22] numerically investigated the performance of the TH and the flow structure in a circular tube using a twisted tape insert equipped with a THS. The results show that the TT insert favors the vortex regime, which significantly increases the heat transfer rate than an ordinary tube.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Spacing Design of Two Alternate Baffles on the Performance of Heat Exchangers

Salhi

Amghar

Filali

et al. 2022

DDF

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The present study investigates numerically the heat transfer process based forced convective flow of an incompressible fluid in a two-dimensional rectangular channel. Two baffles are imposed periodically on the lower and upper walls. The study mainly focused on the influence of the arrangement and spacing separating the baffles on the heat transfer's intensification. The values of the Reynolds number for the present turbulent flow regime were chosen in the range of 104 to 8.73 × 104. The equations resulting from the three conservation laws, namely continuity, Navier-Stokes, and energy equations, are solved numerically based on the finite volume method. SIMPLE algorithm is used to overcome the pressure-velocity coupling, and k-ε model is used for the computation of turbulent patterns. Numerical simulations are carried out to study the dynamic and thermal behavior influenced by the control parameters. The physical quantities calculated are the axial velocity, the local, mean Nusselt numbers and the friction coefficient. The obtained results show that the friction coefficient decreases proportionally with the increase of Re number, and the local Nusselt number increases with the Reynolds number. As the spacing between the baffles decreases, the NR ratio increases, and as the Reynolds number increases, NR decreases NR = 6.13, 5.31, 4.62, and 4.30 for case P1, NR = 5.1, 4.5, 3.89, and 3.64, for case P2, NR = 5.00, 4.45, 8.83, and 3.51, for case P3, for equal Reynolds number, 104, 2×104, 4×104, 8.73×104, respectively.

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Section: Introductionmentioning

confidence: 99%

Effect of the Spacing Design of Two Alternate Baffles on the Performance of Heat Exchangers

Salhi

Amghar

Filali

et al. 2022

DDF

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“…In this research, the thermal mixing performance of hot and cold fluid mixing in intersecting and colliding type converging T-junctions has been investigated numerically by assuming incompressibility of fluid and realizable k-ε turbulence model. This k-ε turbulence model with two equations is widely used in industrial applications [26,27]. This K-ε model is proved to produce satisfactory results [3] This model was selected due to a good performance in flows which possesses strong gradients in temperature or pressure, separation, and recirculation due to turbulence [28].…”

Section: Introductionmentioning

confidence: 99%

A Preliminary Numerical Investigation of Thermal Mixing Efficiency in T-Junctions with Different Flow Configurations

Nuruzzaman¹,

Pao²,

Ejaz³

et al. 2021

IJHT

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When hot and cold fluids flow through a converging T-junction, rapid temperature fluctuations occur in the mixing region due to the thermal mixing of fluids. This temperature fluctuation causes thermal fatigue, which is responsible for the shortening of service life in a T-junction. Hence, the design of T-junction for thermal mixing requires not only superior mixing performance but minimize thermal fluctuation during mixing is also desirable. The objective of the present paper is to determine the thermal mixing performance at the mixing region of T-junction with two different flow configurations. Water, at different inlet temperatures, is used as a working medium and is assumed incompressible. Two types of flow configurations, namely intersecting and colliding regular T-junction with a sidearm pointing at 12 o’clock position have been evaluated in this paper. Realizable k-epsilon turbulence model was assumed, and its validity benchmarked against RANS and RSM-EB turbulence models. The thermal mixing efficiency of both flow configurations is calculated and compared. The results show that the thermal mixing efficiency of both intersecting and colliding mixing tee increases with the increase of distance and time. Intersecting tee shows higher temperature fluctuation than colliding tee at the mixing outlet, but colliding tee shows higher thermal mixing efficiency than intersecting mixing tee.

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“…Range. Fazlay Rubbi et al [12] performed the numerical study to research HT performance increasing and flow behavior in a circular tube using twisted tape insert fitted with HES. The results show that for twisted tape insert with hemispherical extrude surface lead to increase in heat transfer rate above 69.4% compared to plain pipe due to effective vortex flow and best mixing caused by the TT insert.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Enhancement by Turbulence Generator inside Heat Receiver

zaid

Hamzah

2020

QJES

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Tubular heat exchanger (THEX), that has been in numerous engineering applications, represents an apparatus that makes heat to be exchanged between two fluids having different changing in temperatures and kept separated by means of a solid wall. In order to enhance the efficiency of the THEX, the rate of heat transfer at the tube side should be improved. Inserting a twisted tape inside the heat exchanger’s tube is one of the passive techniques that has been widely used to improve the heat transfer especially in air conditioning and cooling, processes of power recovery, processes for food and dairy, and plants for chemical processing. The heat exchanger enhancement is achieved by means of using a twisted tape inserted with twisting ratios (TR) equal to 3.2, 4.4, and 5.5, independently. The influences of 2-D parameters such as Nusselt number and frictional coefficient on the THEX’s effectiveness were investigated. The aim of the study is inserting a twisted tape inside the testing pipe to produced turbulent flow and, therefore, creating large turbulence rate inside the pipe that plays an significant role in improving the transferred heat and increasing the drop in the pressure. In this work, the inserted tape has a width and length equal to 21.5 mm and 1000 mm, respectively. The inner and outer diameters of the used pipes were 23 mm and 22 mm, respectively. The tested sectional length of the THEX was equal to 2000 mm. Reynolds number was changed from 500 to 7000. Results obtained from using twisted inserting tapes with varying TR were compared with result from plain tubes. These results were displayed in the contours show the distribution of the temperature and the trajectory of the flow trajectory by axial velocity for testing the low values of Reynolds number applicability in heat exchanger applications

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Numerical Study of Heat Transfer Enhancement of Turbulent Flow Using Twisted Tape Insert Fitted with Hemispherical Extruded Surface

Cited by 4 publications

References 23 publications

Effect of the Spacing Design of Two Alternate Baffles on the Performance of Heat Exchangers

Effect of the Spacing Design of Two Alternate Baffles on the Performance of Heat Exchangers

A Preliminary Numerical Investigation of Thermal Mixing Efficiency in T-Junctions with Different Flow Configurations

Heat Transfer Enhancement by Turbulence Generator inside Heat Receiver

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