Experimental studies of heat transfer of air in a double-pipe helical heat exchanger

Majidi, Davood; Alighardashi, Hashem; Farhadi, Fatola

doi:10.1016/j.applthermaleng.2018.01.057

Cited by 37 publications

(10 citation statements)

References 16 publications

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“…It is also observed that the overall heat transfer coefficient increases too and log mean temperature difference decreases. Majidi et al [7] the obtained results showed that the overall heat transfer coefficient increases by increasing the Reynolds number. Ramu et al [8].…”

Section: Introductionmentioning

confidence: 95%

Numerical prediction for a heat exchanger performance by employing various orientations of longitudinal fins

Kareem¹,

Mushatet²,

Fag³

2021

UTJES

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This paper studies numerically the impact of installing longitudinal fins on the performance of a DPHE. Different heights were considered for these fins and three different profiles; rectangular, triangular, and semi-circular were investigated. Fins were fixed on the internal surface of the annulus side. The numerical investigation was carried out for counter flow. The study is performed in two cases. The first one was of a constant hot water mass flow rate (mh) at (0.3) kg/s and varying values of cold water mass flow rate (mc) which was from 0.2 to 1 kg/s. The second case was of a constant cold water mass flow rate (mc) at (0.3) kg/s and changing hot water mass flow rate (mh) which was from 0.2 to 1 kg/s. Inlet temperature of hot water was 353k and for cold water was 298k. The results showed that using longitudinal fins enhances the (DPHE) thermal performance. Also, semi-circular profile gave more enhancement in the rate of heat transfer compared to other studied profiles

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Section: Introductionmentioning

confidence: 95%

Numerical prediction for a heat exchanger performance by employing various orientations of longitudinal fins

Kareem¹,

Mushatet²,

Fag³

2021

UTJES

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“…The heat transfer enhancement techniques in a double pipe heat exchanger are classified into passive and active techniques. Passive methods can work without any external aids by a geometric modification such as varying the cross section of the inner pipe [2][3][4][5][6][7][8]. Active methods require external stimulation such as vortex creation by rotating the inner pipe [9].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer characteristics of double pipe heat exchanger having externally enhanced inner pipe

Vijayaragavan¹,

Asok²,

Ganesh³

2023

Acta Polytech

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An investigation on enhancement of heat transfer is carried out for a double pipe heat exchanger in which the outer wall of the inner pipe is provided with circumferential labyrinth passages. Rectangular and triangular cavities with fixed labyrinth tooth thickness, height, and pitch are considered and the effect of added labyrinth structures on the heat transfer characteristics is discussed. A two-dimensional steady numerical simulation is carried out using ANSYS-FLUENT software. The flow Reynolds number equals to 20 000 and 43 000 for the hot and cold fluids, respectively, while other fluid properties are constant. From the numerical analysis carried out in this work, it is identified that the added labyrinth passages in the heat exchange surface improve the heat transfer rate and can reduce the length of the heat exchanger. Numerical predictions agree well with the results obtained from the experiment conducted.

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“…Majidi et al [21] studied the influence of installing a copper-wire fin on the outer area of the internal tube in a double-pipe heat exchanger on the overall heat transfer coefficient. The results showed that the flow rates of hot and cold-water streams significantly affect the heat transfer enhancement and increase it up to 6%.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Heat Transfer and Turbulent Flow in a Baffled Pipe with Different Arrangements

Al-Lami

Mohammed²,

Ali³

et al. 2022

EJENG

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In the heat transfer, fluid flow and energy fields, baffles are an advanced enhancer to improve heat transfer and fluid mixing by working as an obstacle to the flow particles and then increasing the turbulence. The present paper numerically investigates the thermal performance of a circular pipe with a centralized baffle in two arrangements, with a Reynolds number (Re) (ranging from 10,000-50,000) under constant wall heat flux boundary conditions. Ansys Fluent software is used to solve the flow field considering six conical baffles with different Pitch ratios (PR) (from 1 to 5). Results show that baffles shape, arrangement, and PR have a significant impact on the properties of flow and heat transfer. The obtained results show an effective role for the baffles to promote thermal performance when it is used in heated pipes. Heat transfer rate is increased for the baffled pipe by 1-2 compared with the smooth pipe. Moreover, the best value of friction factor, thermal performance, and Nusselt number is recorded at PR= 5 at Re=30000 in the baffled pipe for the second arrangement.

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Experimental studies of heat transfer of air in a double-pipe helical heat exchanger

Cited by 37 publications

References 16 publications

Numerical prediction for a heat exchanger performance by employing various orientations of longitudinal fins

Numerical prediction for a heat exchanger performance by employing various orientations of longitudinal fins

Heat transfer characteristics of double pipe heat exchanger having externally enhanced inner pipe

Characteristics of Heat Transfer and Turbulent Flow in a Baffled Pipe with Different Arrangements

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