Experimental and Numerical Investigation of the Gas Side Heat Transfer and Pressure Drop of Finned Tubes—Part II: Numerical Analysis

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Rene Hofmann ◽  
Heimo Walter
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Numerical Study ◽  
Three Dimensional ◽  
Finned Tube ◽  
Renormalization Group Theory ◽  
Tube Material ◽  
Finned Tubes ◽  
Steady State Temperature ◽  
Volume Method

The heat transfer and pressure drop behavior of segmented circular and helical as well as solid finned tubes are investigated in a three-dimensional numerical study. The simulation is carried out using a finite volume method for calculating the steady-state temperature and flow field of the fluid as well as the temperature distribution of the tube material. For modeling the turbulence, the k-ε turbulence model based on the renormalization group theory (RNG) is used to resolve the near-wall treatment between adjacent fins. All simulations are performed in the Re range between 3500 ≤ Re ≤ 50,000. The influence of Reynolds number and fin geometry (segmented or solid and circular or helical) on the local and global averaged heat transfer and pressure drop was studied. A comparison between solid and segmented finned tube has shown that the heat transfer and pressure drop for the segmented finned tubes is higher. The numerical results are compared with experimental data.

Comparison Between Numerical and Experimental Gas Side Heat Transfer and Pressure Drop of a Tube Bank With Solid and Segmented Circular I-Fins

2012 ◽  
Author(s):  
Rene Hofmann ◽  
Heimo Walter
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Finned Tube ◽  
Three Dimensional Model ◽  
Finned Tubes ◽  
Numerical Predictions ◽  
Staggered Arrangement ◽  
Flow Experiments

In the present work, a comparison between numerical and experimental gas side heat transfer and pressure drop for a tube bundle with solid and segmented circular finned tubes in a staggered arrangement is investigated. For the numerical simulations a three dimensional model of the finned tube are applied. Renormalization group theory (RNG) based k–ε turbulence model was used to calculate the turbulent flow. Experiments have been carried out to validate the numerical predictions. The numerical results for the Nu-number and pressure drop coefficient show a good agreement with the data from measurement. A comparison between solid and segmented finned tubes from the global calculation of the Nu-numbers within the analyzed Re-range shows an enhancement by applying segmented finned tubes rather than finned tubes with solid fins.

Tube Banks Heat Transfer Enhancement Using Conical Fins

2010 ◽  
Author(s):  
Ignacio Carvajal-Mariscal ◽  
Florencio Sanchez-Silva ◽  
Georgiy Polupan
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pressure Drop ◽  
Finned Tube ◽  
Hot Water ◽  
Experimental Results ◽  
Tube Bank ◽  
Finned Tubes ◽  
Tube Banks ◽  
Annular Fins

In this work the heat transfer and pressure drop experimental results obtained in a two step finned tube bank with conical fins are presented. The tube bank had an equilateral triangle array composed of nine finned tubes with conical fins inclined 45 degrees in respect with the tube axis. The heat exchange external area of a single tube is approximately 0.07 m2. All necessary thermal parameters, inlet/outlet temperatures, mass flows, for the heat balance in the tube bank were determined for different air velocities, Re = 3400–18400, and one constant thermal charge provided by a hot water flow with a temperature of 80 °C. As a result, the correlations for the heat transfer and pressure drop calculation were obtained. The experimental results were compared against the analytical results for a tube bank with annular fins with the same heat exchange area. It was found that the proposed tube bank using finned tubes with conical fins shows an increment of heat transfer up to 58%.

Effect of Periodic Imposed Heat Flux on Three-Dimensional Natural Convection in a Partially Heated Cubical Enclosure

2016 ◽  
Vol 831 ◽  
pp. 83-91
Author(s):  
Lahoucine Belarche ◽  
Btissam Abourida
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Study ◽  
Control Volume ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Cubical Enclosure ◽  
Simplec Algorithm ◽  
Volume Method

The three-dimensional numerical study of natural convection in a cubical enclosure, discretely heated, was carried out in this study. Two heating square sections, similar to the integrated electronic components, are placed on the vertical wall of the enclosure. The imposed heating fluxes vary sinusoidally with time, in phase and in opposition of phase. The temperature of the opposite vertical wall is maintained at a cold uniform temperature and the other walls are adiabatic. The governing equations are solved using Control volume method by SIMPLEC algorithm. The sections dimension ε = D / H and the Rayleigh number Ra were fixed respectively at 0,35 and 106. The average heat transfer and the maximum temperature on the active portions will be examined for a given set of the governing parameters, namely the amplitude of the variable temperatures a and their period τp. The obtained results show significant changes in terms of heat transfer, by proper choice of the heating mode and the governing parameters.

Study on Heat Transfer and Resistance Characteristics of H-Type Finned Tube

2013 ◽  
Vol 805-806 ◽  
pp. 1817-1822 ◽  
Author(s):  
Zhang Jun Wang ◽  
Zhuo Xiong Zeng ◽  
Yi Hua Xu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Performance ◽  
Euler Number ◽  
Numerical Study ◽  
Three Dimensional ◽  
Finned Tube ◽  
Comprehensive Performance ◽  
Better Than

Three-dimensional numerical study is performed for heat transfer and resistance characteristics as well as comprehensive performance of two kinds H-type (single and double) finned tube. It is found that the heat transfer and resistance characteristics as well as comprehensive performance of H-type finned tube are influenced by the Reynolds number of gas. With the growth of Reynolds number, the air-side Nusselt number rises gradually and the heat transfer performance gets better and better, whereas the air-side Euler number drops step by step until close to a fixed value. The comprehensive performances of both single H-type finned tube and double ones are weaken progressively. When Reynolds number value is same, the convective heat transfer, pressure drop, air-side Nusselt number and Euler number of single H-type finned tube are bigger than those of double ones. The single H-type finned tube expression is much better than double ones in comprehensive performance and heat transfer.

An Investigation of Heat Transfer and Pressure Drop Enhancement of Various Perforated Circular Finned Tubes at Different Tube Tilt Angles

2021 ◽  
pp. 10295-10338
Author(s):  
Yahya Yaser Shanyour AL-Salman, Ali Sabri Abbas
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Tilt Angle ◽  
Transfer Rate ◽  
Performance Criterion ◽  
Finned Tube ◽  
Finned Tubes ◽  
Global Performance

The thermal and flow performance of the circular annular finned tube heat exchanger with perforated fins were investigated numerically using ANSYS Fluent 2020 software, RNG k-e model with enhanced wall treatment, global performance criterion was introduced as evaluation factor of the heat exchanger performance, the parameters to be investigated were the number of holes, size of hole, tilt angle of the finned tube, fin height and spacing between fins. Agreement was found with literature that the tilt angle causes increase in heat transfer rate and increase in the pressure drop as well, but the change the global performance criterion as function to tilt angle depends on the fin heights, for higher fin heights the effective change of the pressure drop become greater than the increase in the heat transfer rate and the contrast occur in the cases of smaller fin heights, we have found that the perforation in tilted annular circular finned tubes causes an increase in the heat transfer rate and an enhancement in the total heat exchanger performance, increasing the number of holes will enhance the performance of the heat exchanger and the spacing increase reduces the heat exchanger performance.

The Effect of Using Nanofluids on Triangular Microchannel Heat Exchanger Performance

2010 ◽  
Author(s):  
G. Bhaskaran ◽  
H. A. Mohammed ◽  
N. H. Shuaib
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Numerical Study ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Particle Volume ◽  
Microchannel Heat Exchanger

A numerical study is performed to study the effects of using various types of nanofluids on a triangular shaped microchannel heat exchanger (MCHE). The performance of an aluminum MCHE with various types of nanofluids such as Al2O3, CuO, SiO2, Ag and TiO2 and diamond particles with particle volume fraction of 2% using water as base fluid is comprehensively analyzed. The three-dimensional steady, laminar developing flow and conjugate heat transfer of a balanced MCHE were solved using finite volume method. In order to maintain laminar flow in the microchannels, Re number was ranged from 100 to 800. The other parameters tested in this study include the effects of Reynolds number towards the temperature, effectiveness and pressure drop of the MCHE. It is found that nanofluids have improved the temperature profile and heat transfer rate of the MCHE. The increase in pressure drop was minimal while the thermal and hydrodynamic performance of the heat exchanger was enhanced.

Numerical Study of Thermofluid Characteristics of a Double Spirally Coiled Tube Heat Exchanger

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Mahmoud Abdelmagied
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Curvature Ratio ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Enhancing Heat Transfer

In this study, the thermofluid characteristics of double spirally coiled tube heat exchanger (DSCTHE) were investigated numerically. A three-dimensional (3D) computational fluid dynamic (CFD) model was developed using ansys 14.5 software package. To investigate the heat transfer and pressure drop characteristics of DSCTHE, the Realize k–ε turbulence viscous model had been applied with enhanced wall treatment for simulating the turbulent thermofluid characteristics. The governing equations were solved by a finite volume discretization method. The effect of coil curvature ratio on DSCTHE was investigated with three various curvature ratios of 0.023–0.031 and 0.045 for inner tube side and 0.024–0.032–0.047 for annular side. The effects of addition of Al2O3 nanoparticle on water flows inside inner tube side or annular side with different volume concentrations of 0.5%, 1%, and 2% were also presented. The numerical results were carried out for Reynolds number with a range from 3500 to 21,500 for inner tube side and from 5000 to 24,000 for annular side, respectively. The obtained results showed that with increasing coil curvature ratio, a significant effect was discovered on enhancing heat transfer in DSCTHE at the expense of increasing pressure drop. The results also showed that the heat transfer enhancement was increased with increasing Al2O3 nanofluid concentration, and the penalty of pressure drop was approximately negligible.

Heat Transfer and Pressure Drop Characteristics of Finned Tube Banks in Heat Exchanger for Gas Turbine

2004 ◽  
Author(s):  
K. Kawaguchi ◽  
K. Okui ◽  
Y. Hasegawa
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Thermal Power ◽  
Finned Tube ◽  
Finned Tubes ◽  
Thermal Power Generation ◽  
Reduction Of Energy Consumption ◽  
Tube Banks

In recent years the requirement for reduction of energy consumption has been increasing to solve the problems of the global warming and the shortage of petroleum resources. For example in the power generation field, as the thermal power generation occupied 60% of the power generation demand, the improvement of the thermal efficiency is required considerably. This paper described the heat transfer and pressure drop characteristics of the finned tube banks used for the heat exchanger in the thermal power generation. The characteristics were clarified by testing the serrated finned tubes banks for improvement of higher heat transfer and the conventional spiral finned tube banks under the same test conditions. The equations to predict heat transfer coefficient and pressure drop which are necessary on design of the heat exchanger were proposed.

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