A numerical study on condensation flow and heat transfer of refrigerant in minichannels of printed circuit heat exchanger

2019 ◽  
Vol 102 ◽  
pp. 96-111 ◽  
Author(s):  
Zhongchao Zhao ◽  
Yanrui Zhang ◽  
Xudong Chen ◽  
Xiaolong Ma ◽  
Shan Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Printed Circuit ◽  
Flow And Heat Transfer ◽  
Condensation Flow

Numerical Study on Flow and Heat Transfer Performance of Natural Gas in a Printed Circuit Heat Exchanger During Trans-Critical Liquefaction

2020 ◽  
Author(s):  
Ting Ma ◽  
Pan Zhang ◽  
Jie Lian ◽  
Hanbing Ke ◽  
Wei Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Natural Gas ◽  
Numerical Study ◽  
Local Pressure ◽  
Local Flow ◽  
Printed Circuit ◽  
Minimum Value ◽  
Flow And Heat Transfer

Abstract The main cryogenic heat exchanger is a core piece of equipment in the liquefaction of natural gas. The printed circuit heat exchanger is gradually becoming a primary choice for the main cryogenic heat exchanger, because it has good pressure resistance, high efficiency, and compactness. In this work, a numerical simulation is conducted to examine the local flow and heat transfer characteristics of natural gas in the printed circuit heat exchanger during trans-critical liquefaction. It is found that the heat flux density reaches a minimum value and the heat transfer is the worst when the temperature difference between the hot and cold sides is the smallest. Owing to the large variations in physical properties of trans-critical natural gas, the local pressure drop exhibits an upward parabolic shape along the flow direction, and the pressure drop reaches a minimum value near the pseudo-critical point. Finally, the friction factor and heat transfer correlations for natural gas during trans-critical liquefaction are fitted.

scholarly journals Numerical Study on Flow and Heat Transfer Characteristics of Trapezoidal Printed Circuit Heat Exchanger

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1589
Author(s):  
Yuxuan Ji ◽  
Kaixiang Xing ◽  
Kefa Cen ◽  
Mingjiang Ni ◽  
Haoran Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Numerical Study ◽  
Three Dimensional ◽  
Channel Structure ◽  
Complex Flow ◽  
Compact Structure ◽  
Printed Circuit ◽  
Flow And Heat Transfer

Printed circuit heat exchanger (PCHE) is a promising regenerative device in the sCO2 power cycle, with the advantages of a large specific surface area and compact structure. Its tiny and complex flow channel structure brings enhanced heat transfer performance, while increasing pressure drop losses. It is, thus, important to balance heat transfer and flow resistance performances with the consideration of sCO2 as the working agent. Herein, three-dimensional models are built with a full consideration of fluid flow and heat transfer fields. A trapezoidal channel is developed and its thermal–hydraulic performances are compared with the straight, the S-shape, and the zigzag structures. Nusselt numbers and the Fanning friction factors are analyzed with respect to the changes in Reynolds numbers and structure geometric parameters. A sandwiched structure that couples two hot channels with one cold channel is further designed to match the heat transfer capacity and the velocity of sCO2 flows between different sides. Through this novel design, we can reduce the pressure drop by 75% and increase the regenerative efficiency by 5%. This work can serve as a solid reference for the design and applications of PCHEs.

scholarly journals Numerical Study on Flow and Heat Transfer Mechanisms in the Heat Exchanger Channel with V-Orifice at Various Blockage Ratios, Gap Spacing Ratios, and Flow Directions

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Amnart Boonloi ◽  
Withada Jedsadaratanachai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Numerical Results ◽  
Blockage Ratio ◽  
Maximum Heat ◽  
Flow And Heat Transfer ◽  
Maximum Heat Transfer ◽  
Smooth Channel ◽  
Gap Spacing

Numerical assessments in the square channel heat exchanger installed with various parameters of V-orifices are presented. The V-orifice is installed in the heat exchanger channel with gap spacing between the upper-lower edges of the orifice and the channel wall. The purposes of the design are to reduce the pressure loss, increase the vortex strength, and increase the turbulent mixing of the flow. The influence of the blockage ratio and V-orifice arrangement is investigated. The blockage ratio, b/H, of the V-orifice is varied in the range 0.05–0.30. The V-tip of the V-orifice pointing downstream (V-downstream) is compared with the V-tip pointing upstream (V-upstream) by both flow and heat transfer. The numerical results are reported in terms of flow visualization and heat transfer pattern in the test section. The thermal performance assessments in terms of Nusselt number, friction factor, and thermal enhancement factor are also concluded. The numerical results reveal that the maximum heat transfer enhancement is found to be around 26.13 times higher than the smooth channel, while the optimum TEF is around 3.2. The suggested gap spacing for the present configuration of the V-orifice channel is around 5–10%.

scholarly journals Numerical study of natural melt convection in cylindrical cavity with hot walls and cold bottom sink

2013 ◽  
Vol 17 (3) ◽  
pp. 853-864 ◽  
Author(s):  
Abdennacer Ahmanache ◽  
Noureddine Zeraibi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Cylindrical Cavity ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Bulk Temperature ◽  
Flow And Heat Transfer

Numerical study of natural convection heat transfer and fluid flow in cylindrical cavity with hot walls and cold sink is conducted. Calculations are performed in terms of the cavity aspect ratio, the heat exchanger length and the thermo physical properties expressed via the Prandtl number and the Rayleigh number. Results are presented in the form of isotherms, streamlines, average Nusselt number and average bulk temperature for a range of Rayleigh number up to 106. It is observed that Rayleigh number and heat exchanger length influences fluid flow and heat transfer, whereas the cavity aspect ratio has no significant effects.

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