Air-Side Thermal and Drain Performance of Wire-Strip Fin-Tube Heat Exchanger

2012 ◽  
Author(s):  
Hie Chan Kang ◽  
Sun An Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Empirical Correlations ◽  
Tube Heat Exchanger ◽  
Theoretical Predictions ◽  
The Wire ◽  
Fin Tube ◽  
Strip Heat

The purpose of the present study is to investigate the characteristics of pressure drop, heat transfer rate and drainability of a wire-strip heat exchanger modified from the conventional louver fin one. Scaled-up models with the standard and four kinds of wire-strip fins were made, and their thermal and hydraulic performances tested in a wind tunnel. The drainability of the fins was evaluated by measuring the water retained after dipping the heat exchangers. The f and j factors and their ratios for the wire-strip fins are compared with those of the conventional louver fin, and empirical correlations and theoretical predictions were made. The best design for the wire-strip fins showed a better thermal performance per unit fan power than the standard louver fin by several tens of percent. It also retained about half or less of the water.

Finned Elliptical Tubes and Their Application in Air-Cooled Heat Exchangers

1966 ◽  
Vol 88 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Franz J. Schulenberg
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Transfer Surface ◽  
Great Success ◽  
Sufficient Criterion ◽  
Tube Heat Exchanger ◽  
Circular Tubes ◽  
Fin Tube

Finned circular tubes have been used exclusively in air-cooled heat exchangers built for the American petroleum and chemical industries. In Europe, however, other tube geometries, in particular, finned elliptical tubes, have been used with great success. In this paper, the theory of the finned elliptical tube and its application in air-cooled heat exchangers are discussed. Finned circular and elliptical tubes are compared; it is shown that the developed heat transfer surface alone is not a sufficient criterion for predicting the performance of an air-cooled fin-tube heat exchanger.

Prediction of Non-Uniform Frost Distribution on a Fin Tube Heat Exchanger

2013 ◽  
Author(s):  
Jieun Hwang ◽  
Keumnam Cho
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Pump ◽  
Transfer Rate ◽  
Volume Flow Rate ◽  
Local Data ◽  
Tube Heat Exchanger ◽  
Side Pressure ◽  
Fin Tube

Heat exchanger experiences frost on its surface when it operates below 0°C under heating condition of the heat pump. Since frost blocks air flow through the fin tube heat exchanger, it increases air-side pressure drop and deteriorates heat transfer rate of the heat exchanger. Prediction of the frost profiles on the heat exchanger is needed to minimize the unfavorable effect on the heat exchanger by frost. The present study predicts non-uniform frost distribution on the surface of fin-tube heat exchanger and shows its accuracy by comparing with measured profiles. Fin and tube heat exchanger for heat pump was considered for the frost prediction under practical refrigerant and air conditions. Non-uniform frost pattern was predicted by using segment by segment method of the heat exchanger. Heat transfer rate and exit temperature of air and refrigerant for each segment were calculated by applying ε-NTU method. Air volume flow rate in the front of the heat exchanger was decreased as frost goes on. It was utilized for the prediction of the frost formation. Numerically predicted results were compared with measured local data. They agreed within ±10.4% under the ISO 5151 condition.

Effect of Local Frost Characteristics on Thermal Performance of Fin Tube Heat Exchanger Under Frosting Condition

2013 ◽  
Author(s):  
Jeongkeun Kim ◽  
Jieun Hwang ◽  
Keumnam Cho
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Surface Temperature ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Measured Data ◽  
Coolant Temperature ◽  
Maximum Deviation ◽  
Tube Heat Exchanger ◽  
Fin Tube

The present study aimed to measure and predict frost characteristics and heat transfer rate of fin-tube specimen, and predicted them of fin-tube heat exchanger. Test conditions were air temperature from 0.5 to 7 °C, absolute humidity from 3.18 to 4.01 g/kgDA, air velocity from 0.5 to 2.5m/s, and coolant temperature from −15 to −5 °C. The coolant was ethylene-glycol aqueous solution with concentration of 50%. Correlation equations for the average frost thickness and frost surface temperature were proposed. The proposed correlation equation for the average frost thickness and average frost surface temperature agreed with the measured data within the maximum deviation of 20% and 15%. The average frost thickness in front and front mass were predicted and compared with the measured data. They agreed within ±14 and ±23%, respectively. The heat transfer rate was predicted and compared with the measured data. They agreed within ±13% when the total heat transfer rate was over 70W.

scholarly journals Study of the Influence of the Lack of Contact in Plate and Fin and Tube Heat Exchanger on Heat Transfer Efficiency under Periodic Flow Conditions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3779
Author(s):  
Marcin Łęcki ◽  
Dariusz Andrzejewski ◽  
Artur N. Gutkowski ◽  
Grzegorz Górecki
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Air Gap ◽  
Temperature Fields ◽  
Periodic Flow ◽  
Flow Conditions ◽  
Tube Heat Exchanger ◽  
Fin Tube

Plate fin-tube heat exchangers are widely used in air conditioning and refrigeration systems and other industry fields. Various errors made in the manufacturing process can result in the formation of an air gap between the tube and fin. Several numerical simulations were carried out for a symmetric section of plate fin-tube heat exchanger to study the influence of air gap on heat transfer under periodic flow conditions. Different locations and sizes of an air gap spanning 1/2 circumference of the tube were considered for the range of airflow velocities. Velocity and temperature fields for cases with air gap were compared with ideal thermal contact cases. Blocking of heat flow by the gap leads to the reduction of heat transfer rate. Fin discontinuity in the front of the tube causes the smallest reduction of the heat transfer rate in comparison to the ideal tube-fin contact, especially for thin slits. The rear gap position is the worst in the smallest gap range. Therefore, reversing the flow direction can lead to up to a 15% heat transfer increase, if mainly the rear gaps are present. The introduction of a thin slit in the front of the tube leads to convective heat transfer enhancement, which should be further investigated.

The Shell and Tube Heat Exchanger Efficiency and Its Relation to Effectiveness

2003 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Optimum Heat ◽  
Flow Heat ◽  
Shell And Tube

The heat exchanger efficiency is defined as the ratio of the actual heat transfer in a heat exchanger to the optimum heat transfer rate. The optimum heat transfer rate, qopt, is given by the product of UA and the Arithmetic Mean Temperature Difference, which is the difference between the average temperatures of hot and cold fluids. The actual rate of heat transfer in a heat exchanger is always less than this optimum value, which takes place in a balanced counter flow heat exchanger. It is shown that for parallel flow, counter flow, and shell and tube heat exchanger the efficiency is only a function of a single nondimensional parameter called Fin Analogy Number. Remarkably, the functional dependence of the efficiency of these heat exchangers on this parameter is identical to that of a constant area fin with an insulated tip. Also a general algebraic expression as well as a generalized chart is presented for the determination of the efficiency of shell and tube heat exchangers with any number of shells and even number of tube passes per shell, when the Number of Transfer Units (NTU) and the capacity ratio are known. Although this general expression is a function of the number of shells and another nondimensional group, it turns out to be almost independent of the number of shells over a wide range of practical interest. The same general expression is also applicable to parallel and counter flow heat exchangers.

scholarly journals Effects of nanofluids on heat transfer characteristics in shell and tube heat exchanger

2021 ◽  
pp. 76-76
Author(s):  
Sakthivel Perumal ◽  
Vijayan Venkatraman ◽  
Rajkumar Sivanraju ◽  
Addisalem Mekonnen ◽  
Sathish Thanikodi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Zirconium Dioxide ◽  
Heat Transfer Characteristics ◽  
Volume Percentage ◽  
Tube Heat Exchanger ◽  
Transfer Characteristics ◽  
Shell And Tube

Nowadays ensure the performance of heat exchanger is one of the toughest roles in industries. In this work focused on improve the performance of shell and tube heat exchangers by reducing the pressure drop as well as raising the overall heat transfer. This work considered as a different nanoparticles such as Aluminium oxide (Al2O3), Silicon dioxide (SiO2), Titanium oxide (TiO2) and Zirconium dioxide (ZrO2) to form a nanofluids. This nanofluids possesses high thermal conductivity by using of this increase the heat transfer rate in shell and tube heat exchanger. The selected nanofluids are compared to base fluid based on the thermophysical properties as well as heat transfer characteristics. All the heat transfer characteristics are improved by applying of nanofluids particularly higher results are obtained with using of TiO2 and Al2O3 compared to SiO2 and ZrO2. Mixing of nanoparticles increased in terms of volume percentage it will be increases the all Heat transfer characteristics as well as performance of the heat exchanger.

Heat transfer enhancement for fin-tube heat exchanger using vortex generators

2002 ◽  
Vol 16 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Seong-Yeon Yoo ◽  
Dong-Seong Park ◽  
Min-Ho Chung ◽  
Sang-Yun Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Fin Tube

scholarly journals Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

2016 ◽  
Vol 37 (4) ◽  
pp. 137-159 ◽  
Author(s):  
Rafał Andrzejczyk ◽  
Tomasz Muszyński
Keyword(s):  
Heat Transfer ◽  
Surface Modification ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Helical Structure ◽  
Nuclear Industry ◽  
Helical Coil ◽  
Tube Heat Exchanger ◽  
High Heat Transfer ◽  
Coil Heat

Abstract The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

scholarly journals Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

2021 ◽  
Vol 11 (19) ◽  
pp. 9261
Author(s):  
Yun-Seok Choi ◽  
Youn-Jea Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Magnetic Fields ◽  
Heat Transfer Performance ◽  
Permanent Magnets ◽  
Convective Heat Transfer Coefficient ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
Improve Heat Transfer ◽  
Fin Tube

As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

scholarly journals Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1762 ◽  
Author(s):  
Zhe Wang ◽  
Fenghui Han ◽  
Yulong Ji ◽  
Wenhua Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transfer Model ◽  
Enhanced Heat Transfer ◽  
Pump System ◽  
Heat Pump System ◽  
Tube Heat Exchanger ◽  
Exergy Transfer

A marine seawater source heat pump is based on the relatively stable temperature of seawater, and uses it as the system’s cold and heat source to provide the ship with the necessary cold and heat energy. This technology is one of the important solutions to reduce ship energy consumption. Therefore, in this paper, the heat exchanger in the CO2 heat pump system with graphene nano-fluid refrigerant is experimentally studied, and the influence of related factors on its heat transfer enhancement performance is analyzed. First, the paper describes the transformation of the heat pump system experimental bench, the preparation of six different mass concentrations (0~1 wt.%) of graphene nanofluid and its thermophysical properties. Secondly, this paper defines graphene nanofluids as beneficiary fluids, the heat exchanger gains cold fluid heat exergy increase, and the consumption of hot fluid heat is heat exergy decrease. Based on the heat transfer efficiency and exergy efficiency of the heat exchanger, an exergy transfer model was established for a seawater source of tube heat exchanger. Finally, the article carried out a test of enhanced heat transfer of heat exchangers with different concentrations of graphene nanofluid refrigerants under simulated seawater constant temperature conditions and analyzed the test results using energy and an exergy transfer model. The results show that the enhanced heat transfer effect brought by the low concentration (0~0.1 wt.%) of graphene nanofluid is greater than the effect of its viscosity on the performance and has a good exergy transfer effectiveness. When the concentration of graphene nanofluid is too high, the resistance caused by the increase in viscosity will exceed the enhanced heat transfer gain brought by the nanofluid, which results in a significant decrease in the exergy transfer effectiveness.

Sign in / Sign up

Export Citation Format

Share Document