scholarly journals Modification of a recuperator construction with CFD methods

2017 ◽  
Vol 38 (4) ◽  
pp. 567-576
Author(s):  
Wojciech Ludwig ◽  
Daniel Zając
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Velocity Field ◽  
Work Conditions ◽  
Gas Velocity ◽  
Gas Distribution ◽  
Value Changes

Abstract The purpose of the work was initial modification of the construction of a commercially produced heat exchanger – recuperator with CFD (computational fluid dynamics) methods, based on designs and process parameters which were provided. Uniformity of gas distribution in the space between the tubes of the apparatus as well as the pressure drop in it were taken as modification criteria. Uniformity of the gas velocity field between the tubes of the heat exchanger should cause equalization of the local individual heat transfer coefficient values and temperature value. Changes of the apparatus construction which do not worsen work conditions of the equipment, but cause savings of constructional materials (elimination or shortening some parts of the apparatus) were taken into consideration.

The Preliminary Design of Compacted Heat Exchanger Based on Helical Baffles Technique

2017 ◽  
Author(s):  
Wang Cong ◽  
Qiu Jinrong ◽  
Liao Yi
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Preliminary Design ◽  
Turbulent Model ◽  
Flow Properties ◽  
Shell Side

This paper conducted a preliminary design of heat exchanger based on helical baffles technique. The realizable k-ε turbulent model was adopted to simulate the flow properties and heat transfer in the shell side with the computational fluid dynamics software. The numerical results show that the helical baffles heat exchanger offer about 11% higher heat transfer coefficient, 6% higher pressure drop and 10% lesser heat exchanger area than of heat exchanger with segmental baffles under the same heat exchanger power. It could help achieve the goal of reducing volume of heat exchanger with helical baffles technique.

Analysis on the Heat Transfer Performance of Jacketed Tube Heat Exchanger with Different Finned Array

2013 ◽  
Vol 860-863 ◽  
pp. 1478-1483
Author(s):  
Zhong Chao Zhao ◽  
Hao Jun Mi ◽  
Long Yun
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
The Heat Transfer Coefficient

The heat transfer performance of heat exchanger dependents on the pattern of finned array. The heat transfer coefficient of jacketed tube heat exchanger with and without finned array was investigated by computational fluid dynamics. The results reveal that: the heat transfer coefficient of jacketed tube heat exchanger with in-line-fin and staggered-fin increase to the 87.8% and 98.2% of that without finned array, respectively, and with 35.1% and 37.6% increments of pressure drop correspondingly. The heat transfer coefficient of heat exchanger with staggered-fin increased to 5.4% compared with that with in-line-fin.

Investigating the Effect of Fuel Rate Variation in an Industrial Thermal Cracking Furnace With Alternative Arrangement of Wall Burners Using Computational Fluid Dynamics Simulation

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
Hossein Mohammad Ghasemi ◽  
Neda Gilani ◽  
Jafar Towfighi Daryan
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Side Wall ◽  
Base Flow ◽  
Dynamics Simulation ◽  
Rate Variation ◽  
Fuel Rate

A new arrangement of side-wall burners of an industrial furnace was studied by three-dimensional computational fluid dynamics (CFD) simulation. This simulation was conducted on ten calculation domain. Finite rate/eddy dissipation model was used as a combustion model. Discrete ordinate model (DOM) was considered as radiation model. Furthermore, weighted sum of gray gas model (WSGGM) was used to calculate radiative gas properties. Tube skin temperature and heat flux profiles were obtained by solving mass, momentum, and energy equations. Moreover, fuel rate variation was considered as an effective parameter. A base flow rate of fuel (m˙=0.0695kg/s) was assigned and different ratios (0.25 m˙, 0.5 m˙, 2 m˙, and 4 m˙) were assigned to investigate the heat distribution over the furnace. Resulted temperature and heat profiles were obtained in nonuniform mode using the proposed wall burner arrangement. According to the results, despite increased heat transfer coefficient of about 34% for m˙–4 m˙, temperature profile for this rate is too high and is harmful for tube metallurgy. Also, the proper range for fuel rate variation was determined as 0.5–2 m˙. In this range, heat transfer coefficient and Nusselt number for m˙–2 m˙ were increased by 21% and for m˙–0.25 m˙ were decreased by about 28%.

Forced Convection Computational Fluid Dynamics Analysis of Architected and Three-Dimensional Printable Heat Sinks Based on Triply Periodic Minimal Surfaces

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Oraib Al-Ketan ◽  
Mohamed Ali ◽  
Mohamad Khalil ◽  
Reza Rowshan ◽  
Kamran A. Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Minimal Surfaces ◽  
Heat Sink ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Triply Periodic Minimal Surfaces ◽  
Triply Periodic

Abstract The drive for small and compact electronic components with higher processing capabilities is limited by their ability to dissipate the associated heat generated during operations, and hence, more advanced heat sink designs are required. Recently, the emergence of additive manufacturing techniques facilitated the fabrication of complex structures and overcame the limitation of traditional techniques such as milling, drilling, and casting. Therefore, complex heat sink designs are now easily realizable. In this study, we propose a design procedure for mathematically realizable architected heat sinks and investigate their performance using the computational fluid dynamics (CFD) approach. The proposed heat sinks are mathematically designed with topologies based on triply periodic minimal surfaces (TPMSs). Three-dimensional CFD models are developed using the starccm+ platform for uniform heat sinks and topologically graded heat sinks to study the heat transfer performance in forced convection domains. The overall heat transfer coefficient, surface temperature, and pressure drop versus the input heat sources as well as the Reynolds number are used to evaluate the heat sink performance. Moreover, temperature contours and velocity streamlines were examined to analyze the fluid flow behavior within the heat sinks. Results showed that the tortuosity and channel complexity of the Diamond solid-networks heat sink result in a 32% increase in convective heat transfer coefficient compared with the Gyroid solid-network heat sink which has the comparable surface area under the examined flow conditions. This increase is at the expense of increased pressure drops which increases by the same percentage. In addition, it was found that expanding channel size along flow direction using the porosity grading approach results in significant pressure drop (27.6%), while the corresponding drop in convective heat transfer is less significant (15.7%). These results show the importance of employing functional grading in the design of heat sinks. Also, the manufacturability of the proposed designs was assessed using computerized tomography (CT) scan and scanning electron microscopy (SEM) imaging performed on metallic samples fabricated using powder bed fusion techniques. A visible number of internal manufacturing defects can affect the performance of the proposed heat sinks.

The Technical Derivation of Heat Transfer Performance of the Airside of a Novel Pin Design Heat Exchanger Using Computational Fluid Dynamics

2012 ◽  
Author(s):  
Tosha Churitter
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Diameter Ratio ◽  
Transfer Performance ◽  
Extended Surface

Pins are a common type of extended surface used in the field of heat transfer; their main application being in the electronics field. Historically, pins used in heat exchangers have diameters that are considered negligible in comparison to their lengths and are therefore termed as tubes. In this report, the use of pins as an extended surface is investigated for the heat transfer on the airside (cold) of the Compact Advanced Pin Surface Heat Exchanger. The pins are circular in cross section and follow a staggered arrangement. The uniqueness of the pin design is such that they cannot be treated as tubes. Key Pin Design features are as follows: • Pins have a maximum Length: Diameter ratio of 3. • Pin Spacing to Pin Diameter ratio is greater than in traditional arrangements. • Pins function as a primary as well as secondary surface. The heat transfer performance of extended surfaces possessing the above features has not been characterized, using commercially available Computational Fluid Dynamics (CFD) software, in any research specifically focused on applications for the aerospace industry. Based on actual test results, this study specially develops a unique approach that can predict the outlet temperature of the heat exchanger to within 1% accuracy. This ‘developed’ approach is applied over cold-side mass flow rates ranging from 0.05 kg/s to 0.23 kg/s, while keeping the hot side mass flow rate constant at 0.05 kg/s. At worst, the simulation results lie within 5% accuracy and at best the simulation accuracy is 1%, a significant improvement on traditional derivations. This article specifically discusses the methodology developed to analyse the heat transfer performance of the novel pin design using Fluent 6.2. It highlights the current limitations of existing equations as well as the theoretical knowledge gap that currently exists in the analysis of pins as extended heat transfer surfaces in heat exchangers.

The Effect of Fin Geometry on Design of Compact Off-Set Strip Fin High Temperature Heat Exchanger

2005 ◽  
Author(s):  
Sundaresan Subramanian ◽  
Valery Ponyavin ◽  
Clayton Ray De Losier ◽  
Yitung Chen ◽  
E. Hechanova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Exchanger ◽  
Transfer Enhancement ◽  
Heat Exchanger Design ◽  
Helium Gas ◽  
Temperature Heat ◽  
Overall Performance ◽  
Offset Strip Fin

This paper deals with the development of a three-dimensional numerical model to predict the overall performance of an advanced high temperature heat exchanger design, up to 1000°C, for the production of hydrogen by the sulfur iodine thermo-chemical cycle used in advanced nuclear reactor concepts. The design is an offset strip-fin, hybrid plate compact heat exchanger made from a liquid silicon impregnated carbon composite material. The two working fluids are helium gas and molten salt (Flinak). The offset strip-fin is chosen as a method of heat transfer enhancement due to the boundary layer restart mechanism between the fins that has a direct effect on heat transfer enhancement. The effects of the fin geometry on the flow field and heat transfer are studied in three-dimensions using Computational Fluid Dynamics (CFD) techniques. The pre-processor GAMBIT is used to create a computational mesh, and the CFD software package FLUENT that is based on the finite volume method is used to produce the numerical results. Fin dimensions need to be chosen that optimize heat transfer and minimize pressure drop. Comparison of the overall performance between two fin shapes (rectangular versus curved edges) is performed using computational fluid dynamics techniques. Fin and channel dimensions need to be chosen such as to optimize heat transfer performance and minimize pressure drop. The study is conducted with helium gas and liquid salt as the working fluids with a variety of Reynolds number values and fin dimensions. Both laminar and turbulent modeling is performed for the helium side fluid flow. The effect of the fin geometry is performed computational fluid dynamics techniques and optimization studies are performed. The model developed in this paper is used to investigate the heat exchanger design parameters in order to find an optimal design.

scholarly journals CFD and Experimental Analysis of a Falling Film outside Smooth and Helically Grooved Tubes

2014 ◽  
Vol 6 ◽  
pp. 915034 ◽  
Author(s):  
Cenk Onan ◽  
Derya Burcu Ozkan ◽  
Serkan Erdem
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transfer Coefficient ◽  
Surface Temperature ◽  
Transfer Coefficient ◽  
Experimental Results ◽  
Smooth Tube ◽  
Falling Film ◽  
Grooved Tube

Simultaneous heat and mass transfer are investigated in a falling film outside grooved and smooth tubes. A numerical analysis of the helically trapezoidal-grooved and reference smooth tube was performed in the computational fluid dynamics program “Ansys Fluent 14.” The three-dimensional model drawings in the x, y, and z coordinates are used, and the effects of the falling film outside the helically grooved tube on the surface temperature and surface heat transfer coefficient are determined. The average surface temperature, heat transfer coefficient, and Nu values are determined experimentally for a constant heat flux. An uncertainty analysis and Nu correlation for the grooved tube are also provided in this study. The Reynolds number varied between 50 and 350 for the falling film and between 1500 and 3500 for air. Using a computational fluid dynamics (CFD) analysis for the reference smooth tube, the experimental results are validated within 2–12% difference. The experimental results are also within 6–13% of the grooved tubes.

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