scholarly journals Experimental Investigation of the Thermofluid Characteristics of Shell-and-Plate Heat Exchangers

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5304
Author(s):  
Howard Lee ◽  
Ali Sadeghianjahromi ◽  
Po-Lun Kuo ◽  
Chi-Chuan Wang
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Large Contribution ◽  
Transfer Performance ◽  
Shell Side ◽  
Plate Heat

An experimental study regarding the thermofluid characteristics of a shell-and-plate heat exchanger with different chevron angles (45°/45°, 45°/65°, and 65°/65°) with a plate diameter of 440 mm was carried out. Water was used as the working fluid on both sides and the corresponding temperatures ranged from 30–70 °C. The flow rate on the plate or shell side ranged from 10–60 m3/h. The effects of chevron angles on the heat transfer and fluid flow characteristics of shell-and-plate heat exchangers were studied in detail. With regard to the heat transfer performance on the plate side, a higher chevron angle (65°/65°) resulted in a significantly better performance than a low chevron angle (45°/45°). The effect of the chevron angle became even more pronounced at high Reynolds numbers. Unlike the plate side, an increase in the chevron angle had a negative effect on the heat transfer performance of the shell side. Additionally, this opposite effect was more prominent at low Reynolds numbers due to the comparatively large contribution of the manifold. The friction factor increased appreciably with the increase in the chevron angle. However, when changing the chevron angle from 45°/45° to 65°/65°, the increase in the friction factor was about 3–4 times on the plate side while it was about 2 times on the shell side. This can be attributed to the presence of the distribution/collection manifold on the shell side. Empirical correlations for the Nusselt number and friction factor were developed for different combinations of chevron angles with mean deviations of less than 1%.

Heat Transfer Performance of Different Nanofluids Flows in a Helically Coiled Heat Exchanger

2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Transfer Performance

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.

scholarly journals Numerical study of flow patterns and heat transfer in mini twisted oval tubes

2015 ◽  
Vol 26 (12) ◽  
pp. 1550140 ◽  
Author(s):  
Amin Ebrahimi ◽  
Ehsan Roohi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Critical Role ◽  
Reynolds Numbers ◽  
Flow Patterns ◽  
Working Fluid ◽  
Transfer Performance ◽  
Temperature Dependent ◽  
Overall Performance

Flow patterns and heat transfer inside mini twisted oval tubes (TOTs) heated by constant-temperature walls are numerically investigated. Different configurations of tubes are simulated using water as the working fluid with temperature-dependent thermo-physical properties at Reynolds numbers ranging between 500 and 1100. After validating the numerical method with the published correlations and available experimental results, the performance of TOTs is compared to a smooth circular tube. The overall performance of TOTs is evaluated by investigating the thermal-hydraulic performance and the results are analyzed in terms of the field synergy principle and entropy generation. Enhanced heat transfer performance for TOTs is observed at the expense of a higher pressure drop. Additionally, the secondary flow generated by the tube-wall twist is concluded to play a critical role in the augmentation of convective heat transfer, and consequently, better heat transfer performance. It is also observed that the improvement of synergy between velocity and temperature gradient and lower irreversibility cause heat transfer enhancement for TOTs.

Measurements of Thermal Performance of the Regenerator of a Cryocooler with a high Number of Transfer Units Value

1996 ◽  
Vol 210 (4) ◽  
pp. 341-352 ◽  
Author(s):  
P-H Chen ◽  
Z-C Chang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Friction Factor ◽  
Heat Transfer Performance ◽  
Working Fluid ◽  
Transfer Performance ◽  
Thomson Effect ◽  
Empirical Correlations ◽  
External Tube ◽  
Improved Model

Hundreds of stacked wire screens are used in the regenerator matrix of a common cryocooler. The number of transfer units of such a matrix (denoted as NTUm) may well exceed 60. However, most of the earlier studies reported are limited to studies of regenerators with NTUm values less than 60, as the single-blow method was employed to measure the NTUm value of the regenerator matrix. Furthermore, in these earlier studies, the effect of heat transfer from the working fluid to the external tube and the Joule-Thomson effect were neglected. In the present study, three regenerators having high NTUm values have been constructed and a transient single-blow technique has been employed to measure the friction factor and the heat transfer performance of these regenerators. In addition, an improved model has been adopted to correct the shortcomings of the earlier studies. Empirical correlations have been provided for the relation between the friction factor and Reynolds number and between the Nusselt number and Reynolds number. The correlation with smaller NTUm values agreed well with those reported in earlier studies.

Review: Condensation and Evaporation Characteristics of Low GWP Refrigerants in Plate Heat Exchangers

2016 ◽  
Vol 24 (02) ◽  
pp. 1630004 ◽  
Author(s):  
Byung Hoon Shon ◽  
Seung Won Jeon ◽  
Yongchan Kim ◽  
Yong Tae Kang
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Saturation Temperature ◽  
Transfer Performance ◽  
Plate Heat ◽  
Frictional Pressure Drop ◽  
Evaporation Heat ◽  
Lower Heat

In this paper, condensation and evaporation characteristics of low global warming potential (GWP) refrigerants such as R-1234yf and R-1234ze series are reviewed. This review focuses on heat transfer and pressure drop in plate heat exchangers. Mass flux is considered as an important factor while saturation temperature is not for condensation and evaporation process in plate heat exchangers. The dryout phenomenon occurs occasionally and gives greatly harmful impact on evaporation heat transfer. It is found that R-1234yf and R-1234ze(E) give slightly lower heat transfer performance than R-134a for both condensation and evaporation processes. Generally, low GWP refrigerants presented in this review give lower heat transfer coefficient and higher frictional pressure drop than the conventional refrigerants. Nevertheless, R-1234ze(Z) gives superior heat transfer performance than other refrigerants in condensation. R-32 gives remarkable performance in evaporation, but it gives relatively high GWP compared to other low GWP refrigerants.

Airside Performance of Wavy Fin-and-Tube Heat Exchangers: Data With Larger Diameter Tube

2010 ◽  
Author(s):  
Huau Pao Lo ◽  
Chinghua Hung ◽  
Chi-Chuan Wang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Low Reynolds Number ◽  
Transfer Performance ◽  
Frictional Performance ◽  
Low Reynolds

This study examines the airside fin-and-tube heat exchangers having a larger diameter tube Dc = 16.59 mm) with the tube row ranging from 1 to 16. It is found that the effect of tube row on the heat transfer performance is quite significant, and the heat transfer performance deteriorates with the rise of tube row. The performance deteriorates with the rise of tube row. The performance drop is especially pronounced at the low Reynolds number region. Actually more than 85% drop of heat transfer performance is seen for Fp ∼ 1.7 mm as the row number is increased from 1 to 16. Upon the influence of tube row on the frictional performance, an unexpected row dependence of the friction factor is encountered. The effect of fin pitch on the airside performance is comparatively small for N = 1 or N = 2. However, a notable drop of heat transfer performance is seen when the number of tube row is increased, and normally higher heat transfer and frictional performance is associated with that of the larger fin pitch.

scholarly journals Study on Testing Methods for the Heat Transfer Performance of Plate Heat Exchangers

2021 ◽  
Vol 245 ◽  
pp. 01048
Author(s):  
Bin Ren ◽  
Xuchen Zhu ◽  
Yannan Du ◽  
Zhe Pu ◽  
Hongliang Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
High Heat ◽  
Plate Heat Exchanger ◽  
Transfer Performance ◽  
Plate Heat ◽  
High Heat Transfer ◽  
Wilson Plot

Plate heat exchangers are new-type compact heat exchangers with high heat transfer efficiency widely used in heating, food, medicine, shipbuilding and petrochemical industries. However, only the laboratory testing can accurately obtain the real heat transfer and flow resistance performance of plate heat exchanger. In this paper, the basic principles of modified Wilson plot method and equal velocity method are firstly introduced. Then the testing system including flow chart and testing instruments are discussed. Finally, contrast experiments using the different two methods are conducted. The results showed that for plate heat exchangers with equal channel, the equal velocity method and modified Wilson plot method can both be used to test the convective heat transfer performance of plate heat exchanger. The equal velocity method is recommended because the deformation of plate is relatively smaller.

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