Numerical study on the effects of design parameters on the heat transfer performance of coaxial deep borehole heat exchanger

Pin fin heat exchanges are often used in cooling of high thermal loaded electronic components due to their excellent heat transfer performance. However, the pressure drop in such heat exchanges is usually much higher than that in others, so their overall heat transfer performance is seriously reduced. In order to reduce the pressure drop and improve the overall heat transfer performance for pin fin heat exchangers, porous metal pin arrays are used and the performance of fluid flow and heat transfer in heat exchanger unit cells are numerically studied. The Forchheimer-Brinkman extended Darcy model and two-equation heat transfer model for porous media are employed and the effects of Reynolds number (Re), permeability (K) and pin fin cross-section forms are studied in detail. The results show that, with proper selection of governing parameters, the overall heat transfer performance of porous pin fin heat exchanger is much better than that of traditional solid pin fin heat exchanger; the overall heat transfer performance of long elliptic porous pin fin heat exchanger is the best, that is, the heat transfer per unit pressure drop of such heat exchanger is the highest and the maximum value of the heat transfer over pressure drop is obtained at K = 2×10−7 m2.

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Numerical Study on the Effect of Tube Rows on the Heat Transfer Characteristic of Dimpled Fin

Advances in Mechanical Engineering ◽

10.1155/2014/637052 ◽

2014 ◽

Vol 6 ◽

pp. 637052 ◽

Cited By ~ 1

Author(s):

Xuehong Wu ◽

Lihua Feng ◽

Dandan Liu ◽

Hao Meng ◽

Yanli Lu

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Transfer Characteristic ◽

Average Nusselt Number ◽

Heat Transfer Performance ◽

Numerical Study ◽

Transfer Characteristic ◽

Transfer Performance ◽

Heat Transfer Characteristics ◽

Tube Heat Exchanger

The dimpled fin has excellent heat transfer performance and has attracted a lot of attention to apply on the fin and tube heat exchanger. A study presents to investigate the effects of number of tube rows on the air-side heat transfer characteristics of dimpled fin for velocity ranging from 1 to 3 m/s. The Q/Δ P and Q/((Δ P × V)) are used to evaluate the heat transfer performance of the heat exchanger. The results show that the dimpled arrangement can change the mainstream direction, increase the disturbance, and enhance the heat transfer. With the increase of the number of tube rows, the average Nusselt number decreases and Q/Δ P and Q/((Δ P × V)) increase gradually. Compared with the multipipe tube rows, the performance of two-row tube is better.

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Numerical Study on Heat Transfer Performance of Crossflow Fin-tube Heat Exchanger Depending on Different Fan Positions

Transactions of the Korean Society of Mechanical Engineers B ◽

10.3795/ksme-b.2015.39.3.271 ◽

2015 ◽

Vol 39 (3) ◽

pp. 271-278

Author(s):

Won Hyung Kim ◽

Tae Seon Park

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Transfer Performance ◽

Numerical Study ◽

Transfer Performance ◽

Tube Heat Exchanger ◽

Fin Tube

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Numerical Study on Thermal Hydraulic Performance of Supercritical LNG in Zigzag-Type Channel PCHEs

Energies ◽

10.3390/en12030548 ◽

2019 ◽

Vol 12 (3) ◽

pp. 548 ◽

Cited By ~ 5

Author(s):

Zhongchao Zhao ◽

Yimeng Zhou ◽

Xiaolong Ma ◽

Xudong Chen ◽

Shilin Li ◽

...

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Pressure Drop ◽

Mass Flux ◽

Heat Transfer Performance ◽

Numerical Study ◽

Hydraulic Performance ◽

Operating Conditions ◽

Bend Angle ◽

Transfer Performance

In this paper, we study a promising plate-type heat exchanger, the printed circuit heat exchanger (PCHE), which has high compactness and is suitable for high-pressure conditions as a vaporizer during vaporization. The thermal hydraulic performance of supercritical produce liquefied natural gas (LNG) in the zigzag channel of PCHE is numerically investigated using the SST κ-ω turbulence model. The thermo-physical properties of supercritical LNG from 6.5 MPa to 10MPa were calculated using piecewise-polynomial approximations of the temperature. The effect of the channel bend angle, mass flux and inlet pressure on local convection heat transfer coefficient, and pressure drop are discussed. The heat transfer and pressure loss performance are evaluated using the Nusselt and Euler numbers. Nu/Eu is proposed to evaluate the comprehensive heat transfer performance of PCHE by considering the heat transfer and pressure drop characteristics to find better bend angle and operating conditions. The supercritical LNG has a better heat transfer performance when bend angle is less than 15° with the mass flux ranging from 207.2 kg/(m2·s) to 621.6 kg/(m2·s), which improves at bend angle of 10° and lower compared to 15° at mass flux above 414.4 kg/(m2·s). The heat transfer performance is better at larger mass flux and lower operating pressures.

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Numerical Study and Optimization of Corrugation Height and Angle of Attack of Vortex Generator in the Wavy Fin-and-Tube Heat Exchanger

Journal of Heat Transfer ◽

10.1115/1.4040609 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 4

Author(s):

Wei Li ◽

Tariq Amin Khan ◽

Weiyu Tang ◽

W. J. Minkowycz

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Transfer Performance ◽

Numerical Study ◽

Angle Of Attack ◽

Transfer Performance ◽

Maximum Heat ◽

Tube Heat Exchanger ◽

Multi Objective ◽

Maximum Heat Transfer

Wavy fins have been considered as an alternative of the straight fins in compact heat exchangers (CHEs) for better heat transfer performance, which can be augmented by considering vortex generators (VGs). This work is related to numerical investigation and optimization of corrugation height of fin and angle of attack of delta winglet type VGs in a wavy fin-and-tube heat exchanger. For this purpose, three-dimensional (3D) Reynolds-averaged Navier-Stokes analysis and a multi-objective genetic algorithm (MOGA) with surrogate modeling are performed. Numerical simulation is carried out to study the effect of delta winglets with varying the corrugation height of wavy fin in three rows of tubes with staggered tube arrangements. The corrugation height (H) and angle of attack (α) vary from 0.3 mm to 1.8 mm and 15 deg to 75 deg, respectively. Results are illustrated by investigating the flow structures and temperature contours. Results show that increasing the corrugation height of wavy fin and angle of attack of delta winglets enhances the heat transfer performance of heat exchanger while friction factor is also increased. Employing delta winglets has augmented the thermal performance for all corrugation heights and superior effect is observed at a higher corrugation. To achieve a maximum heat transfer enhancement and a minimum pressure drop, the optimal values of these parameters (H and α) are calculated using the Pareto optimal strategy. For this purpose, computational fluid dynamics (CFD) data, a surrogate model (neural network), and a multi-objective GA are combined. Results show that optimal orientation of delta winglets with respect to corrugation height can improve both the thermal and hydraulic performance of the heat exchanger.

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