Influence of Circuitry Arrangement on the Pressure Drops of Two-Row Finned Tube Evaporators

2000 ◽  
Vol 123 (1) ◽  
pp. 100-103 ◽  
Author(s):  
Chi-Chuan Wang ◽  
Min-Sheng Liu ◽  
Jin-Sheng Leu
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Cross Flow ◽  
Finned Tube ◽  
Parallel Flow ◽  
Pressure Drops ◽  
Heat Addition ◽  
Side Pressure ◽  
Flow Pattern Transition ◽  
Flow Circuit

This study experimentally investigates the effect of circuitry on the refrigerant-side pressure drops of plate finned tube evaporators. Experiments were performed with countercross, parallel-cross, and z-shape arrangements. The results showed that the parallel-cross-flow circuit gives a lower pressure drop than other arrangements. Generally, the refrigerant-side pressure drops increase with air frontal velocities. However, for G=200 kg/m2s˙s and parallel flow, the pressure drops decrease with increase of air frontal velocity. This unusual characteristic is most likely related to the flow pattern transition when subjected to heat addition.

Effect of Circuit Arrangement on the Performance of Plate Finned Tube Heat Exchangers Under Dehumidifying Conditions

1999 ◽  
Author(s):  
Min-Sheng Liu ◽  
Jin-Sheng Leu ◽  
Chi-Chuan Wang ◽  
Vince C. Mei
Keyword(s):  
Heat Conduction ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Finned Tube ◽  
Parallel Flow ◽  
Pressure Drops ◽  
Flow Pattern Transition ◽  
Flow Circuit

Abstract This study experimentally investigates the effect of circuitry on the performance of plate finned tube evaporators. Experiments were carried out with the heat exchangers having 1-circuit arrangements. A total of six circuitry were examined in this study, including two counter-cross, two parallel-cross, and two z-shape arrangements. The results showed that the counter-cross arrangement gives the best performance. However, heat conduction along the fins may offset the benefits of the counter-cross arrangement. In addition, the pressure drop of refrigerant-side increased with frontal velocities. Among the six 1-circuit arrangements, the parallel-cross flow circuit would produce a larger pressure drop than other arrangements. However, for G = 200 kg/m2·s and parallel flow, the pressure drops decrease with increase of the frontal velocity. The unusual characteristics are likely related to the flow pattern transition subjected to heat addition. The location of refrigerant inlet does not significantly affect the performance of heat exchangers.

Flow Pattern and Pressure Drop in Highly Concentrated Slurries Transportation Pipelines

2011 ◽  
Vol 281 ◽  
pp. 179-182
Author(s):  
Hai Lu ◽  
Jun Yin ◽  
Yi Xing Yuan ◽  
Biao Wang ◽  
Hong Wei Chen ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Particle Concentration ◽  
Fine Particles ◽  
Pipe Wall ◽  
Flow Patterns ◽  
Coarse Particles ◽  
Pressure Drops ◽  
Frictional Losses ◽  
High Concentrations

Flow pattern and pressure drop in highly concentrated slurries transportation pipelines were discussed. The particles are settling, and tend to settle down to the bottom of pipes due to the action of gravity force forming different flow patterns which can be indicated by particle concentration profile. Three distinct flow patterns can be observed for different particle size distribution at different velocities: fully stratified, partially stratified and fully suspended flow patterns. As for pressure drop, it is well known that pressure drops in pipeline flows of slurries are strongly dependent on the flow pattern developed in a pipeline. Furthermore, fine particles suspended in water make the water more viscous, and increase the friction. In case of coarse particles, having larger volume, they have the tendency to contact with the pipe wall and with the other coarse particles more times, which increase the friction of flow. Meanwhile, coarse particles are lifted by the pressure difference generated as they rotate in the liquid preventing the coarse particles from settling down which results in less friction. The mixture of particles of different sizes is helpful to reduce pressure drop in pipeline flow slurries. Narrow grading particles tend to have high frictional losses, while broad grading particles have low frictional losses at high concentrations.

Flow Characteristics and Frictional Pressure Drops of Gas-Liquid Two-Phase Flow in Mini-Micro Pipes and at Vena Contract and Expansion

2007 ◽  
Author(s):  
Hiroyasu Ohtake ◽  
Hideyasu Ohtaki ◽  
Yasuo Koizumi
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Liquid Velocity ◽  
Flow Patterns ◽  
Experimental Results ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Frictional Pressure Drop

The frictional pressure drops and two-phase flow patterns of gas-liquid two-phase flow in mini-micro pipes and at vena contract and expansion were investigated experimentally. Test liquid was water; test gas was argon. The diameter of the test mini-pipe was 0.5, 0.25 and 0.12 mm, respectively. The pressure drop data and the flow pattern were collected over 2.1 < Ug < 92.5 m/s for the superficial gas velocity and 0.03 < Ul < 10 m/s for the superficial liquid velocity. The experimental results show that the flow patterns were slug, churn, ring and annular flows; pure bubbly flow pattern was not observed in a range of the present experimental conditions. The two-phase friction multiplier data for D > 0.5 mm showed to be in good agreement with the conventional correlations. On the other hand, the two-phase friction multiplier data for D < 0.25 mm differed from the calculated values by the conventional correlations. Then, thickness of liquid film around a gas plug and size of gas core were estimated and the effect of frictional pressure drop on channel size was discussed through Knudsen Number of gas and instability on liquid-gas interface. The coefficients of sudden enlargement and sudden contraction in mini-pipes for the gas-water two-phase flow were modified from the present experimental results.

Air side pressure drop in plate finned tube heat exchangers

2019 ◽  
Vol 99 ◽  
pp. 24-29 ◽  
Author(s):  
Saša Marković ◽  
Branislav Jaćimović ◽  
Srbislav Genić ◽  
Miloš Mihailović ◽  
Uroš Milovančević ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Heat Exchangers ◽  
Finned Tube ◽  
Side Pressure

scholarly journals Analytical Performance Analysis of Cross Flow Louvered Fin Automobile Radiator

2018 ◽  
Vol 172 ◽  
pp. 02003
Author(s):  
R Badgujar Pankaj ◽  
S Rangarajan ◽  
S. R Nagaraja
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cross Flow ◽  
Maximum Deviation ◽  
Side Pressure ◽  
Proposed Model ◽  
Louvered Fin ◽  
Louvered Fins

The objective of the present paper is to propose an analytical model for calculating performance parameter of a radiator having rectangular tube with louvered fins. The theoretical effectiveness, heat transfer rate, outlet temperatures of both air and coolant are determined using effectiveness-NTU method. The coolant and air side pressure drop is also calculated. The proposed procedure is validated with experimetal results available in the literature and the GT model. It is found that the maximum deviation in the heat transfer rate calculated from proposed model is 10.97%, the coolant and air outlet temperatures is 2.75% and variation in pressure drop is about 3.29%.

Frictional Pressure Drops of Two-Phase R-134A Flow in Horizontal and Vertical U-Type Wavy and Straight Tubes

2006 ◽  
Author(s):  
Ing Youn Chen ◽  
Yu-Shi Wu ◽  
Yu-Juei Chang ◽  
Chi-Chuan Wang
Keyword(s):  
Pressure Gradient ◽  
Flow Pattern ◽  
Straight Tube ◽  
Two Phase ◽  
Pressure Drops ◽  
Flow Pattern Transition ◽  
The Difference ◽  
R 134A ◽  
Gradient Ratio ◽  
Phase Pressure

This study presents the measurements of R-134a two-phase frictional pressure gradient subject to vertical and horizontal arrangements of a U-type wavy tube with inner diameter of 5.07 mm and a curvature ratio of 5. The ratio between two-phase pressure gradients of U-bend and straight tube is about 2.5 - 3.5. For the straight tube, the frictional two-phase pressure gradient ratio between the vertical and horizontal arrangements is marginally higher (1.0 - 1.2) for annular flow pattern at x &gt; 0.5, and is 1.0 - 1.4 for the U-bend in the wavy tube. The higher resistance in the vertical arrangement is due to the buoyancy force against the flow inertia. However, for x &lt; 0.5, this ratio is gradually increased due to the difference of flow pattern. The ratio is increased to 1.8 in the straight tube. For the U-bend, the ratio is 2.1 for flow entering the upper tube and is 1.5 for flow entering the lower tube at x = 0.1 and G = 200 kg/m2·s. For the vertical wavy tube, additional effects like the flow pattern transition, liquid flow reversal, and freezing slug may cause additional pressure drops.

Flow pattern transition characteristics in vibrated gas-solid fluidized bed of Geldart B magnetite powder using pressure drop signals analysis

2018 ◽  
Vol 327 ◽  
pp. 358-367 ◽  
Author(s):  
Yadong Zhang ◽  
Yuemin Zhao ◽  
Liang Dong ◽  
Chenlong Duan ◽  
Enhui Zhou ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Fluidized Bed ◽  
Flow Pattern Transition
Sign in / Sign up

Export Citation Format

Share Document