scholarly journals Influence of Perforated Fin on Flow Characteristics and Thermal Performance in Spiral Finned-Tube Heat Exchanger

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 556 ◽  
Author(s):  
Hyung Lee ◽  
Jaiyoung Ryu ◽  
Seong Lee
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Thermal Performance ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Finned Tube ◽  
Reference Case ◽  
Ansys Fluent ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger

The present study conducts the numerical investigation of flow characteristics and thermal performance of spiral finned-tube heat exchangers. The effects of location of perforations (90°, 120°, and 150°) on heat transfer and pressure drop are analyzed for the air-side. The commercial computational fluid dynamics code ANSYS Fluent (V.17.0) is used for simulations with the RNG k-ε model based on the Reynolds-averaged Navier–Stokes equations. The velocity field, Colburn j-factor, and friction factor are analyzed to evaluate the heat transfer and pressure drop characteristics. Because of the flow through the perforations, the boundary layers on the fin surfaces are interrupted. This results in increased flow disturbances close to the fin, and the heat transfer performance increases compared to the reference case. The pressure drop, which is one of the disadvantages of spiral finned tubes comparing to plate or circular fins, decreases with perforations on the fin. Overall, the cases with perforated fin exhibit greater performance of area goodness factor considering the relationship between the heat transfer and the pressure drop.

scholarly journals Numerical Investigation of Finned-tube Heat Exchanger with Circular, Elliptical & Rectangular Tubes

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Finned Tube ◽  
Ansys Fluent ◽  
Tube Heat Exchanger ◽  
Circular Tubes ◽  
Finned Tube Heat Exchanger ◽  
Rectangular Tubes

A three dimensional numerical study has been conducted on finned-tube heat exchanger with multiple rows of tubes using ANSYS (Fluent). The objective of this study is to numerically investigate finned tube heat exchanger with different type of tubes such as circular, elliptical and rectangular tubes. As circular tubes has much pressure drop so elliptical and rectangular tubes has been introduced in order to reduce pressure drop. As well as heat transfer has also been examined. The finite volume based CFD code ANSYS Fluent 16.2 is used to calculate the flow and temperature fields and by applying SIMPLEC algorithm. At low velocity of air and water, nothing significant occurred for the combination of tubes. At high velocity in maximum tube combination there was heat transfer (HT) enhancement and pressure drop reduction when compared with circular tubes only in case of air. When the combinations of circular, elliptical and rectangular tubes has been compared with circular tube heat exchanger (CTHX) heat transfer reduces as well as pressure drop (PD) also reduces for air. In case of water vapor HT and PD behaves the same. When those combinations has been compared with elliptical tube HX, for air in some cases heat transfer remains same and on other case it increases. For pressure drop in case of air, in some cases it reduces and on other cases it reduces. For elliptical tube HX for the fluid water vapor HT and PD both remains same or reduces. This work has not been with conducted any numerical simulation on rectangular Heat exchanger reason behind it there isn’t any existence of this kind of heat exchanger. However, it could be numerically conducted to examine the results between those combination and rectangular heat exchanger.

scholarly journals Research on the Thermal Hydraulic Performance and Entropy Generation Characteristics of Finned Tube Heat Exchanger with Streamline Tube

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5408
Author(s):  
Zuoqin Qian ◽  
Qiang Wang ◽  
Song Lv
Keyword(s):  
Heat Exchanger ◽  
Entropy Generation ◽  
Thermal Performance ◽  
Flow Characteristics ◽  
Hydraulic Performance ◽  
Finned Tube ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Overall Performance ◽  
Present Simulation

Thermal hydraulic performance of the fin-and-tube heat exchanger is presented in this paper. The purpose of this investigation was to investigate the heat transfer mechanism and flow characteristics in the finned tube heat exchanger with streamline tube. The streamline tube in this paper had the streamline cross section which was composed of a semicircle and a half diamond. Three-dimensional numerical simulation was presented and validated by the experiment and the other numerical simulation from public articles. The present simulation had good agreement with the experimental results. The difference of the j factor and f factor between the experimental results and present simulation results by k-ε-enhance model was less than 7.6%. The geometrical parameters were considered as every single variable to investigate the thermal hydraulic performance. The results showed that smaller transversal and larger tube pitch provided greater compactness and better thermal performance. Moreover, a larger angle was not only beneficial to enhance the thermal performance, but also helpful to improve the overall performance. Secondly, the effects of angle on the heat transfer performance and fluid flow characteristics were investigated as the perimeter kept constant. It was shown that the overall performance of the streamline tube was better than the circular tube. Lastly, the entropy generation including frictional entropy generation and the thermal entropy generation were analyzed. It can be concluded that by using the streamline tube, the wake region can be obviously reduced, and thermal performance can be improved.

Performance Evaluation of Tube-in-Tube Heat Exchanger Using Nanofluids

2015 ◽  
Vol 787 ◽  
pp. 72-76 ◽  
Author(s):  
V. Naveen Prabhu ◽  
M. Suresh
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Thermal Performance ◽  
Transfer Rate ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Element Analysis ◽  
Tube Heat Exchanger

Nanofluids are fluids containing nanometer-sized particles of metals, oxides, carbides, nitrides, or nanotubes. They exhibit enhanced thermal performance when used in a heat exchanger as heat transfer fluids. Alumina (Al2O3) is the most commonly used nanoparticle due to its enhanced thermal conductivity. The work presented here, deals with numerical simulations performed in a tube-in-tube heat exchanger to study and compare flow characteristics and thermal performance of a tube-in-tube heat exchanger using water and Al2O3/water nanofluid. A local element-by-element analysis utilizing e-NTU method is employed for simulating the heat exchanger. Profiles of hot and cooling fluid temperatures, pressure drop, heat transfer rate along the length of the heat exchanger are studied. Results show that heat exchanger with nanofluid gives improved heat transfer rate when compared with water. However, the pressure drop is more, which puts a limit on the operating conditions.

HEAT TRANSFER AND PRESSURE DROP CHARACTERISTICS OF AIR COOLED FINNED TUBE HEAT EXCHANGER

2017 ◽  
Author(s):  
In-Cheol Chu ◽  
Kil Won Park ◽  
Woo Jin Jeon ◽  
Hyo Seong Seol ◽  
Tae-Soon Kwon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Finned Tube ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger

Air-Side Heat Transfer and Pressure Drop Characteristics of Peripheral Fin Heat Exchangers

2010 ◽  
Author(s):  
Bruno F. Pussoli ◽  
Jader R. Barbosa ◽  
Luciana W. da Silva ◽  
Massoud Kaviany
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Thermal Conductance ◽  
Particle Diameter ◽  
Finned Tube ◽  
Open Loop ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Neighboring Level

We present an experimental evaluation of the peripheral finned-tube heat exchanger. In this novel compact evaporator geometry, the air-side is composed by an arrangement of open-pore cells formed by radial fins whose bases are attached to the tubes and whose tips are connected to peripheral fins. Each fin arrangement is made up of six radial fins and six peripheral fins forming a hexagon-like structure. The air-side fin configuration is composed of three levels of fin arrangement, each characterized by the length of radial fin and mounted with a 30° offset from its neighboring level. Experimental data on the air-side heat transfer and pressure drop were generated in an open-loop wind tunnel calorimeter. A one-dimensional theoretical model based on the theory of porous media has also been developed to predict the thermal-hydraulic behavior of the heat exchanger. The model incorporates the actual fin geometry into the calculation of the air-side porosity. The air-side permeability is calculated according to the Kozeny-Carman model with the particle diameter definition due to Whitaker and the friction factor correlation due to Ergun. The model overpredicts the air-side thermal conductance by less than 15% for air flow rates higher than 14 L/s. The air-side pressure drop is underpredicted by the model, but still within the limits encountered in the literature. The analysis is complemented with an entropy generation minimization analysis in order to demonstrate the procedure for obtaining an optimized configuration of the heat exchanger.

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