Study on the overall heat transfer coefficient for the tube-in-tube heat exchanger used in mixed-gases coolers

2002 ◽  
Author(s):  
M. Q. Gong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Mixed Gases

scholarly journals Experimental Investigation Of Heat Transfer Characteristics Of Nanofluid Using Parallel Flow, Counter Flow And Shell And Tube Heat Exchanger

2015 ◽  
Vol 62 (4) ◽  
pp. 509-522 ◽  
Author(s):  
R. Dharmalingam ◽  
K.K. Sivagnanaprabhu ◽  
J. Yogaraja ◽  
S. Gunasekaran ◽  
R. Mohan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube

Abstract Cooling is indispensable for maintaining the desired performance and reliability over a very huge variety of products like electronic devices, computer, automobiles, high power laser system etc. Apart from the heat load amplification and heat fluxes caused by many industrial products, cooling is one of the major technical challenges encountered by the industries like manufacturing sectors, transportation, microelectronics, etc. Normally water, ethylene glycol and oil are being used as the fluid to carry away the heat in these devices. The development of nanofluid generally shows a better heat transfer characteristics than the water. This research work summarizes the experimental study of the forced convective heat transfer and flow characteristics of a nanofluid consisting of water and 1% Al2O3 (volume concentration) nanoparticle flowing in a parallel flow, counter flow and shell and tube heat exchanger under laminar flow conditions. The Al2O3 nanoparticles of about 50 nm diameter are used in this work. Three different mass flow rates have been selected and the experiments have been conducted and their results are reported. This result portrays that the overall heat transfer coefficient and dimensionless Nusselt number of nanofluid is slightly higher than that of the base liquid at same mass flow rate at same inlet temperature. From the experimental result it is clear that the overall heat transfer coefficient of the nanofluid increases with an increase in the mass flow rate. It shows that whenever mass flow rate increases, the overall heat transfer coefficient along with Nusselt number eventually increases irrespective of flow direction. It was also found that during the increase in mass flow rate LMTD value ultimately decreases irrespective of flow direction. However, shell and tube heat exchanger provides better heat transfer characteristics than parallel and counter flow heat exchanger due to multi pass flow of nanofluid. The overall heat transfer coefficient, Nusselt number and logarithmic mean temperature difference of the water and Al2O3 /water nanofluid are also studied and the results are plotted graphically.

scholarly journals Optimization of Earth Air Tube Heat Exchanger for Cooling Application Using Taguchi Technique

2020 ◽  
Vol 38 (4) ◽  
pp. 845-862
Author(s):  
Saif Nawaz Ahmad ◽  
Om Prakash
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Pipe Material ◽  
Ground Heat Exchanger ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
The Earth ◽  
Inner Diameter

Earth air tube heat exchanger (EATHE) is one of the passive technologies which utilize the earth stored heat (renewable energy) for heating/cooling the buildings. EATHE releases heat to earth for cooling space in summer, making the earth a heat sink and extracts earth-stored energy for heating space in winter and makes the earth a heat source. This paper optimizes the Length of the ground heat exchanger and overall heat transfer coefficient of earth air heat exchanger using the Taguchi technique for cooling application. For this purpose, we select six factors such as installation depth of Pipe (A), Pipe's inner diameter (B), Thermal conductivity of pipe material (C), Inlet air temperature (D), Outlet air temperature (E), Inlet air velocity (F). All these factors are taken at three levels, and we select an L27 orthogonal array for experimental runs. The ground heat exchanger's Length and the overall heat transfer coefficient were then calculated for each experimental run. In the Taguchi method, we find the signal to noise ratio for an optimal combination of all six factors and ANOVA to find the order of influencing parameters and their percentage contributions for both the objective parameters. According to our results, the best combination for all the six factors for ground heat exchanger length and overall heat transfer coefficient were A1B1C3D1E3F1 and A2B3C2D3E1F3, respectively. The highest and lowest influencing factors for ground heat exchanger length were the pipe's inner diameter and the pipe's installation depth with their contribution factors of 69.12 and 0.32%, respectively. In contrast, the highest and lowest influencing factors for the overall heat transfer coefficient were the pipe's inner diameter and thermal conductivity of pipe material with their contribution factors of 75.97and 0%, respectively. Hence the order of influence of all the six factors for both the objective parameters was BEFDCA.

scholarly journals Performance Analysis of Shell and Tube Type Heat Exchanger Using Aluminium Oxide (Al2O3) Nano-Particle

2021 ◽  
Vol 9 (9) ◽  
pp. 157-164
Author(s):  
Paritosh Singh
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Solid Particles ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Evacuated Tube

Abstract: Research in convective heat transfer using suspensions of nanometer sized solid particles in a base fluid started only over the past decade. Recent investigations on nanofluids, as such suspensions are often called, indicate that the suspended nanoparticles markedly change the transport properties and heat transfer characteristics of the suspension. The very first part of the research work summarizes about the various thermo physical properties of Al2O3 Nanofluid. In evacuated tube solar water heating system nanofluids are used as primary fluid and DM water as secondary fluid in Shell and Tube Heat Exchanger. The experimental analysis of Shell and Tube heat exchanger integrated with Evacuated tube solar collector have been carried out with two types of primary fluids. Research study of shell and tube heat exchanger is focused on heat transfer enhancement by usage of nano fluids. Conventional heat transfer fluids have inherently low thermal conductivity that greatly limits the heat exchange efficiency. The result of analysis shows that average relative variation in LMTD and overall heat transfer coefficient is 24.56% and 52.0% respectively. The payback period of system is reduced by 0.4 years due to saving is in replacement cost of Evacuated Tube Collector. Keywords: ETC; Nanofluid; LMTD; Thermal Conductivity; Overall heat transfer coefficient

scholarly journals Effective Overall Heat Transfer Coefficient Solver in a Triple Concentric-Tube Heat Exchanger

2019 ◽  
Vol 70 (6) ◽  
pp. 2040-2043
Author(s):  
Sinziana Radulescu ◽  
Loredana Irena Negoita ◽  
Ion Onutu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Total Thermal Resistance ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient

A relation for calculation of the effective overall heat transfer coefficient in a triple concentric-tube heat exchanger is proposed. The relation of the effective overall heat transfer coefficient is obtained based on total thermal resistance and it is applied within a case study for thermal analysis of two triple concentric-tube heat exchangers with different geometries, hot fluids and operating conditions. Through case study it is found that the values of effective overall heat transfer coefficient can be obtained with acceptable errors, up to 3 % for both heat exchangers.

scholarly journals Heat transfer analysis in counter flow shell and tube heat exchanger using of design of experiments

2021 ◽  
pp. 77-77
Author(s):  
Sakthivel Perumal ◽  
Dinesh Sundaresan ◽  
Rajkumar Sivanraju ◽  
Nega Tesfie ◽  
Kamalakannan Ramalingam ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Fluid Film ◽  
Heat Transfer Analysis ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube

In this research aimed to estimate the Overall heat transfer coefficient of counter flow Shell and Tube heat exchanger. Heat transfer is the phenomenon to analysis of heat transfer from one medium of fluid to another medium of fluid, it is considered as a major role in industrial applications. Numerous heat exchangers are available, in this research considered as shell and tube heat exchanger. Overall Heat Transfer Coefficient (OHTC) informed that three major factors are influenced as passing of fluid (film) media coefficient inside the tubes, circulating of fluid (film) media coefficient over in the shell and the resistance of wall made on metal. In this study Taguchi L9 Orthogonal array is executed to found the overall heat transfer coefficient with effective process parameters. Three major parameters are considered for this work are coil diameter (25 mm, 30 mm and 35 mm), Baffle thickness (15 mm, 20 mm and 25 mm) and Baffle gap (200 mm, 300 mm and 400 mm. Baffle plate thickness is highly significant factor for this experiment.

The Design, Analysis, and Fabrication of an Additively Manufactured Twisted Tube Heat Exchanger

2017 ◽  
Author(s):  
John D. Bernardin ◽  
Kyle Ferguson ◽  
David Sattler ◽  
Seung-Jun Kim
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Rapid Development ◽  
Steel Shell ◽  
Tube Heat Exchanger ◽  
Twisted Tube ◽  
Overall Heat Transfer Coefficient ◽  
Cfd Analyses

The rapid development of Additive Manufacturing (AM) technologies has provided engineers with new methods to design and fabricate complex mechanisms. AM offers unique methods to allow for integration and simplification of components, reduced manufacturing time, fabrication of complex-shaped objects, improvements upon existing designs, and extending the creative design space which engineers rely on for ingenuity. For many applications, heat exchanger performance can be improved by reducing its size, increasing the overall heat transfer coefficient and surface area, and making more efficient use of the mechanical structure for heat exchange. Traditional manufacturing often limits or prohibits many of these enhancements due to increased manufacturing and assembly costs. This study explored using AM to design and fabricate a compact twisted tube stainless steel shell and tube heat exchanger that would improve upon all of the features just mentioned. This paper discusses the design of the heat exchanger and the AM technique used to fabricate a prototype. The manuscript will show via CFD analyses, how the heat transfer area of the unit was improved 18% and the overall heat transfer coefficient as increased by 40% over a traditional round tube heat exchanger with an identical footprint. Further, the study will show how AM was leveraged to combine five manufacturing steps into one to fabricate a prototype, fully functional twisted tube heat exchanger.

scholarly journals Effect of nanoparticles on heat transfer in heat exchangers

2015 ◽  
Vol 37 ◽  
pp. 199
Author(s):  
Ali Mahrooghi ◽  
Mohammad Moghiman
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Water Pressure ◽  
Two Phase ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient

In this paper, forced convection flow and heat transfer of a Al2O3/Water nanofluid have beeninvestigated numerically by single and two phase (volume of fluid) models. Nanofluid flows inside the innertube of the isothermally concentric circular and sinusoidal double tube heat exchangers while hot pure waterflows in the outer tube. The single-phase and two-phase models is used to simulate the nanofluid forcedconvection of 2% and 3% volume concentrations. The renormalization group k-ε model is used to simulateturbulence in ANSYS FLUENT 15.0. Results show that the overall heat transfer coefficient increases withnanoparticle volume concentrations in the heat exchangers. The highest overall heat transfer coefficient rates aredetected, for each concentration and shape, corresponding to the highest flow rate for the sinusoidal tube heatexchanger . The maximum overall heat transfer coefficient enhancement is 220% for the particle volumeconcentration of 3% at the inner tube of concentric sinusoidal double tube heat exchanger corresponding to flowrate =10 LPM. The results reveal that the Al2O3/water pressure drop along the inner tube of circular andsinusoidal double tube heat exchanger increases by about 3% and 5% for volume concentrations of 2% and 3%,respectively, given flow rate compared to the base fluid.Comparison of these results with Rohit S. Khedkar‘spublished experimental data, showed good agreement.

Numerical simulation of the effect of baffle cut and baffle spacing on shell side heat exchanger performance using CFD

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Swanand Gaikwad ◽  
Ashish Parmar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Numerical Results ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Shell And Tube ◽  
Two Parameters

AbstractHeat exchangers possess a significant role in energy transmission and energy generation in most industries. In this work, a three-dimensional simulation has been carried out of a shell and tube heat exchanger (STHX) consisting of segmental baffles. The investigation involves using the commercial code of ANSYS CFX, which incorporates the modeling, meshing, and usage of the Finite Element Method to yield numerical results. Much work is available in the literature regarding the effect of baffle cut and baffle spacing as two different entities, but some uncertainty pertains when we discuss the combination of these two parameters. This study aims to find an appropriate mix of baffle cut and baffle spacing for the efficient functioning of a shell and tube heat exchanger. Two parameters are tested: the baffle cuts at 30, 35, 40% of the shell-inside diameter, and the baffle spacing’s to fit 6,8,10 baffles within the heat exchanger. The numerical results showed the role of the studied parameters on the shell side heat transfer coefficient and the pressure drop in the shell and tube heat exchanger. The investigation shows an increase in the shell side heat transfer coefficient of 13.13% when going from 6 to 8 baffle configuration and a 23.10% acclivity for the change of six baffles to 10, for a specific baffle cut. Evidence also shows a rise in the pressure drop with an increase in the baffle spacing from the ranges of 44–46.79%, which can be controlled by managing the baffle cut provided.

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