scholarly journals Numerical Investigation on Flow and Heat Transfer Characteristics of Supercritical Liquefied Natural Gas in an Airfoil Fin Printed Circuit Heat Exchanger

2017 ◽  
Author(s):  
Zhongchao Zhao ◽  
Kai Zhao ◽  
Dandan Jia ◽  
Pengpeng Jiang ◽  
Rendong Shen
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Natural Gas ◽  
Hydraulic Performance ◽  
Liquefied Natural Gas ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Printed Circuit ◽  
Flow And Heat Transfer ◽  
Staggered Arrangement

As a new kind of highly compact and efficient micro-channel heat exchanger, printed circuit heat exchanger (PCHE) is a promising candidate satisfying the heat exchange requirements of liquefied natural gas (LNG) vaporization at low and high pressure. The effects of airfoil fin arrangement on heat transfer an flow resistance were numerically investigated using supercritical liquefied natural gas (LNG) as a working fluid. The thermal properties of supercritical LNG were tested by utilizing a REFPROF software database. Numerical simulation was performed using FLUENT. The inlet temperature of supercritical LNG was 121 K,and its pressure was 10.5MPa. The reference mass flow rate of LNG was set 1.22 g/s for the vertical pitch Lv = 1.67 mm and the staggered pitch Ls = 0 mm, with the Reynolds number of about 3750. The SST k-ω model with enhanced wall treatment was selected by comparing with the experimental data. The airfoil fin PCHE had better thermal-hydraulic performance than that of the straight channel PCHE. Moreover, the airfoil fins with staggered arrangement displayed better thermal performance than that of the fins with parallel arrangement. The thermal-hydraulic performance of airfoil fin PCHE was improved with increasing Ls and Lv. Moreover, Lv  affected on the Nusselt number and pressure drop of airfoil fin PCHE more obviously. In conclusion, a sparser staggered arrangement of fins showed a better thermal-hydraulic performance in airfoil fin PCHE.

scholarly journals Effects of Fin Arrangements on Thermal Hydraulic Performance of Supercritical Nitrogen in Printed Circuit Heat Exchanger

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 861
Author(s):  
Shan Yang ◽  
Zhongchao Zhao ◽  
Yong Zhang ◽  
Zhengchao Chen ◽  
Min Yang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Evaluation Criteria ◽  
Hydraulic Performance ◽  
Ansys Fluent ◽  
Printed Circuit ◽  
Flow And Heat Transfer ◽  
Transverse Distance ◽  
Fluent Simulation ◽  
Staggered Arrangement

The printed circuit heat exchanger (PCHE) with discontinuous fins is a novel type of compact and highly efficient plate heat exchanger, which has superior thermal hydraulic performance. The morphology and characteristics of the flow channel greatly affect the performance of the PCHE. The discontinuous airfoil fins are used in PCHE channel design because they can affect the flow and heat transfer by increasing the heat transfer area and the disturbance in the channel. In this paper, the effects of different staggered distance (Ls) and transverse distance (Lv) of airfoil fin arrangements on the heat transfer and flow of supercritical nitrogen in the PCHE are numerically simulated using ANSYS Fluent. Simulation results and subsequent analysis show that the appropriate decrease in Ls and reduction in Lv between the two rows of fins can improve the convective heat transfer of the PCHE. A fully staggered arrangement of fins (Ls = 1.2) and an appropriate increase in the Lv can mitigate pressure drop. The comprehensive performance of different channel geometries is compared by the performance evaluation criteria (PEC) in this study. It is shown that considering flow resistance and heat transfer, the comprehensive heat transfer performance can be enhanced by properly increasing the staggered distance and the vertical distance between fins. When Ls = 1.2 mm and Lv = 1.25 mm, the PEC value of the staggered channel is the highest, which is 11.6% higher than that of the parallel channel on average.

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 investigation on saturated boiling flow and heat transfer of mixture refrigerant in a vertical rectangular mini-channel

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 617-627
Author(s):  
Jie Chen ◽  
Weihua Cai ◽  
Shulei Li ◽  
Yan Ren ◽  
Hongqiang Ma ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Liquefied Natural Gas ◽  
Gas Field ◽  
Flow And Heat Transfer ◽  
Boiling Flow ◽  
Saturated Boiling

Plate-fin heat exchanger with rectangular minichannels, as a type of high-perfor- mance compact heat exchangers, has been widely used in liquefied natural gas field. However, the studies on saturated boiling flow and heat transfer for mixture refrigerant in plate-fin heat exchanger have been scarcely explored, which are helpful for designing more effective plate-fin heat exchanger using in liquefied natural gas field. Therefore, in this paper, the characteristics of saturated boiling flow and heat transfer for mixture refrigerant in rectangular minichannels of plate-fin heat exchanger were studied numerally based on validated model. Then, the effect of different parameters (vapor quality, mass flux, and heat flux) on heat transfer coefficient and frictional pressure drop were discussed. The results indicated that the boiling heat transfer coefficient and pressure drop are mainly influenced by quality and mass flux while heat flux has little influence on them. This is due to the fact that the main boiling mechanisms were forced convective boiling and the evaporation of dispersed liquid phase while nucleate boiling is slight.

Effectiveness of a shell and helically coiled tube heat exchanger operated with gold nanofluids at low concentration: A multi-level factorial analysis

2020 ◽  
pp. 1-39
Author(s):  
Marina B. Fogaça ◽  
Daniele Toniolo Dias ◽  
Sergio L. Gómez ◽  
Jhon Jairo Ramirez Behainne ◽  
Rozane de Fátima Turchiello
Keyword(s):  
Heat Transfer ◽  
Gold Nanoparticles ◽  
Heat Exchanger ◽  
Volumetric Flow Rate ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Helically Coiled Tube ◽  
Multi Level

Abstract This work assesses the thermal performance of gold nanofluids as cooling liquid in a shell and helically coiled tube (SHCT) heat exchanger built in bench-scale. Tests planned under a multi-level factorial experimental design were carried out to evaluate the effects caused by the volumetric fraction of the gold nanoparticles, the volumetric flow rate of the working fluid and the inlet temperature of the hot fluid (water) on the SHCT heat exchanger effectiveness. Spherical gold nanoparticles with mean diameter of 14±2 nm were produced from the Turkevich's method to be used in two concentrations of about 10-5 %vol. The heat transfer tests were performed at volumetric flow rates of 20, 30 and 40 L/h for both working fluids using heated water at inlet temperatures of 40, 50 and 60°C. Results showed that the less concentrated nanofluid was comparatively more efficient, suggesting the presence of a range of values of the gold concentration for the existence of an improvement on the effectiveness in the heat transfer.

Parametric Study of a Horizontal Tube Heat Exchanger for LNG Submerged Combustion Vaporiser

2014 ◽  
Vol 700 ◽  
pp. 667-677
Author(s):  
Qing Li ◽  
Zhi Yin Duan ◽  
Qing Yu Wang ◽  
Rong Liu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Natural Gas ◽  
Computer Model ◽  
Parametric Study ◽  
Single Phase ◽  
Horizontal Tube ◽  
Liquefied Natural Gas ◽  
Tube Heat Exchanger ◽  
Submerged Combustion

LNG (Liquefied Natural Gas) submerged combustion vaporiser is applied to convert Liquefied natural gas to gas phase natural gas through using the hot combustion gas generated from submerged combustion. This paper investigated the vaporisation and heat transfer process of a single horizontal tube, a simplified model, to simulate the heat transfer of circular tube heat exchanger used in LNG submerged combustion vaporiser. This work provides a useful computer model for the design of heat exchanger used in LNG submerged combustion vaporiser. The overall heat transfer and vaporisation process of the tube was separated into single-phase liquid, two-phase mixture and single-phase vapour heat transfer regions for calculation and analysis. Through development of a dedicated computer model, a parametric study was carried out to analyse the effects of geometrical size and operating conditions on inner surface convective heat transfer of tube. The results of study suggested that the preferable tube surface temperature for design was found between 280 K and 288 K in order to avoid frost deposition. The minimum tube length required for the overall vaporisation is predicted to be about 16 m when the inner tube diameter set between 0.24 m and 0.28 m.

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