Study on the Air-Side Heat Transfer and Pressure Drop for Fin-Tube Heat Exchangers

2002 ◽  
Author(s):  
Ji Hwan Jeong ◽  
Keun Sun Chang ◽  
Young Chel Kweon ◽  
Sang Jae Lee ◽  
Min Kyu Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Unit Area ◽  
Numerical Results ◽  
Experimental Measurements ◽  
Air Velocity ◽  
Fin Tube ◽  
Good Agreement

Experimental measurements and numerical analysis have been carried out in order to investigate performances of air-side heat transfer and pressure drop for six types of heat exhcangers with various fin shapes. An air-enthalpy calorimeter is used in this work. Numerical analysis shows a good agreement with experimental measurements. Measurements for six types of heat exchangers at various air-velocity are compared with each other. Heat transfer per unit area appears to be nearly the same in the range of 0.7~0.9 m/s while it varies within 3% at 1.5 m/s. The numerical results show that most of heat transfer takes place through fins for all types and majority of heat transfer happens from the 1st row.

Simulation Investigation on Multi-Unit Parallel-Flow Type Condenser with Flat Tubes Distribution

2013 ◽  
Vol 423-426 ◽  
pp. 1910-1913
Author(s):  
Jian Rong Du ◽  
Zu Yi Zheng ◽  
Jun Hua Wan ◽  
Yi De Wang ◽  
Zhong Min Wan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Air Velocity ◽  
Flat Tube ◽  
Tube Arrangement ◽  
First Pass ◽  
Flat Tubes

Three heat exchangers, all of which have 38 tubes in total and 6 passes, with different tube arrangements were simulation investigated in laboratory. The effect of flat tube distribution on heat transfer performance and pressure drop characteristic was simulation investigated. The effect of different air velocity and flow on heat transfer performance and pressure drop characteristic was simulation investigated too. The results show that similar tube distribution has little effect on heat transfer but has great effect on pressure drop. It was found the tube arrangement from first pass to sixth pass is 10,9,6,5,4,4 has the best heat transfer performance and its pressure drop is small. The heat transfer and pressure drop increase with the air velocity and refrigerant flow.

Experimental Investigation and Comparison on Fin Surfaces Performance of Flat Tube Heat Exchangers

2011 ◽  
Vol 354-355 ◽  
pp. 389-393 ◽  
Author(s):  
Jun Qi Dong ◽  
Qian Chen ◽  
Wu Jie Wei
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Transfer Enhancement ◽  
Air Velocity ◽  
Flat Tube ◽  
Louvered Fin ◽  
Performance Of Heat Transfer ◽  
Offset Strip Fin

An experimental study has been carried out to investigate the heat transfer and pressure drop characteristics of flat tube heat exchangers with plain, wavy, louvered and offset strip fin surfaces. Results are presented as plots of Colburn j factor and friction factor f against Reynolds in the range of 600-6500. Additionally, the dimensional heat transfer coefficient and pressure drop are presented as a function of frontal air velocity. Finally, two comparison methods are adopted to evaluate the air side performance of the plain fin, wavy fin, louvered fin and offset strip fin surface. The results show that the offset strip fin has the best performance of heat transfer enhancement.

Experimental Investigation on Multi-Unit Parallel-Flow Type Condenser with Flat Tubes Distribution

2014 ◽  
Vol 701-702 ◽  
pp. 1233-1236
Author(s):  
Lv Xian Zeng ◽  
Zu Yi Zheng ◽  
Jun Hua Wan ◽  
Xi Chen ◽  
Zhong Min Wan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Air Velocity ◽  
Flat Tube ◽  
The Third ◽  
Flat Tubes ◽  
Simulation Results

Three heat exchangers, all of which have 38 tubes in total and 6 passes, with different tube arrangements were manufactured to be experimental investigated in laboratory. The effect of flat tube distribution on heat transfer performance and pressure drop characteristic was experimental investigated. The effect of different air velocity and flow on heat transfer performance and pressure drop characteristic was also experimental investigated. The results show that similar tube distribution has little effect on heat transfer quality but has great effect on pressure drop. It was found the third arrangement has the best heat transfer and its pressure drop is small. Thus the third arrangement is the best solution. The heat transfer and pressure drop increase with the air velocity and refrigerant flow, so a proper value should be chosen, it was found that the simulation results were mainly agreement with the experimental results.

Modeling an Installation of Recuperative Heat Exchangers for an Aero Engine

2010 ◽  
Author(s):  
Dimitrios Missirlis ◽  
Kyros Yakinthos ◽  
Olivier Seite ◽  
Apostolos Goulas
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Thermodynamic Cycle ◽  
Experimental Measurements ◽  
Exhaust Gas ◽  
Cfd Model ◽  
Pressure Losses ◽  
Aero Engine ◽  
Porosity Model

This work presents the complete effort to model the presence of an integrated system of heat exchangers mounted in the exhaust nozzle of an aero engine which uses an alternative but more efficient thermodynamic cycle. The heat exchangers are operating as heat recuperators exploiting part of the thermal energy of the turbine exhaust gas to preheat the compressor outlet air before combustion and to reduce pollutants and fuel consumption. The presence of the heat exchangers enforces a significant pressure drop in the exhaust gas flow which can affect the overall efficiency of the thermodynamic cycle and the potential benefit of this technology. For this reason it is important to optimize the operation of the system of heat exchangers. The main target of this optimization effort is the minimization of the pressure losses for the same amount of heat transfer achieved. The optimization is performed with the combined use of experimental measurements and CFD methods. Since the CFD modeling is taking into consideration the overall geometry of the exhaust nozzle of the aero engine where the heat exchangers are mounted, the presence of the latter is unavoidably modeled with the use of a porosity model for practical reasons, having to do with CPU and memory requirements. The porosity model is taking into account the pressure drop and heat transfer behaviour of the heat exchangers and was developed and validated with the use of detailed experimental measurements. For the validation of the CFD model, isothermal experimental measurements carried out for laboratory conditions in a 1:1 model of a quarter of the exhaust nozzle of the aero engine, including four full-scale heat exchangers, were used. The CFD results were in good agreement with the experimental measurements and the same flow structures and problematic regions were detected. Thus, a complete 3-D CFD model of the overall exhaust nozzle of the aero engine was created and validated which at the next step formed the basis for the optimization of the overall aero engine installation for real engine operating conditions. The improved design of the aero engine installation presented decreased pressure losses in relation to the initial design and a more balanced mass flow distribution, showing the applicability of the overall methodology and its advantages for producing efficient engineering solutions for similar setups.

scholarly journals Heat Transfer Correlations for Star-Shaped Fins

2021 ◽  
Vol 11 (13) ◽  
pp. 5912
Author(s):  
Mladen Bošnjaković ◽  
Ante Čikić ◽  
Simon Muhič ◽  
Mario Holik
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Laboratory Tests ◽  
Correlation Coefficients ◽  
Test Results ◽  
Air Velocity ◽  
Staggered Arrangement ◽  
Fin Thickness

Star-shaped fins are a newer type of fin for which correlations for heat transfer and pressure drop do not yet exist in the literature. Therefore, correlation equations for air-side heat transfer and pressure drop in a finned heat exchanger with star-shaped stainless-steel fins in staggered arrangement were developed in this work. To obtain these correlations, a numerical analysis of the basic heat exchanger geometry and another 21 variants of heat exchanger geometry was performed using computational fluid dynamics, and then the results of laboratory tests of a model of heat exchangers with star-shaped fins were used. In the numerical analysis, the fin pitch, the fin thickness, and the air velocity at the inlet to the heat exchanger were varied. The Nusselt (Nu) and Euler (Eu) numbers were determined for each variation analyzed. Initial correlations for Nu and Eu were derived using the least-squares deviation method. The correlation coefficients thus obtained were adjusted to agree with the results of the laboratory tests. The deviation of the final obtained correlation for Nu from the experimental test results was up to 10% in the range of Re < 3500, whereas for higher values of Re, the deviation was less than 2%. The Eu correlation deviated from experimental results up to 19% in the range of Re < 4000, whereas in the range of Re > 5600, the deviation was less than 1%. The correlations were valid in the range 2000 < Re < 16,000.

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