scholarly journals Fabrication and Experimental Analysis of Heat Transfer Characteristics of Acetone /Water by using Tube in Tube and Shell and Tube Heat Exchanger

Cooling is essential to maintain the required efficiency and reliability in a wide range of products such as automobiles, high and medium cogeneration power plants, high power laser systems. Part of heat load amplification and the heat fluxes induced by more industrial products, cooling is one of the industry's main technical problems such as manufacturing, transport and in microelectronics. The main content of the paper is to study the LMTD (logarithmic mean temperature difference), Heat transfer Coefficient and Effectiveness (ε) of combined heat exchanger using acetone/water mixture as a function of a different mass flow rates. This paper deals with the experimental study on the three different heat exchangers like tube in tube, shell and tube and combined (tube in tube & shell and tube) heat exchanger with acetone/water mixture mostly to check the elevation of convective heat transfer coefficient, LMTD, effectiveness, overall heat transfer coefficient. This experimentation work give a summary of, the experimental study of the forced convective heat transfer and flow characteristics of a 25% acetone consisting of 75% water. Acetone/water mixture flow in to a parallel, counter direction in the tube in tube, shell and tube heat exchanger and combined heat exchanger under laminar flow conditions. A maximum increase in the coefficient of convective heat transfer of 58.4% and an effectiveness of 48.5% is recorded. However, combined heat exchanger provides better heat transfer characteristics than parallel and counter flow tubular and shell and tube heat exchanger due to the multi-pass flow of acetone/water. The overall heat transfer coefficients, Reynolds number, logarithmic mean temperature difference, the effectiveness of the acetone/water are also studied and the results are presented in tabular columns and figures.

Author(s):  
Cenk Onan ◽  
Derya B. Ozkan ◽  
Levent Ceran

Internally grooved copper tubes are used extensively in HVAC applications, direct expansion batteries and air or water cooled heat exchangers. The advantage of internally grooved copper tubes in evaporator and condenser units is an increase in the refrigerant-side heat transfer coefficient. When an internally grooved tube heat exchanger and a smooth-tube heat exchanger with the same dimensions are compared, the overall heat transfer coefficient and convective heat transfer coefficient are found to increase in different ratios. In addition to this difference, the refrigerant side pressure is found to be a function of the groove geometry, pitch space and choice of refrigerant. In this study, which is different from previous studies in the literature performed using single internally grooved tube condensers and evaporators, refrigerant R404-A is studied in the internally grooved tube evaporator. The heat transfer in the evaporator described here is 30% better than that observed in a conventional smooth-copper-tube evaporator. In the internally grooved tube, the internal surface area is 68% larger than that inside the smooth reference tube. As a result, the convective heat transfer coefficient inside the internally grooved tube is found to be lower than that in the smooth tube.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Swanand Gaikwad ◽  
Ashish Parmar

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.


2017 ◽  
Vol 45 ◽  
pp. 155-163 ◽  
Author(s):  
S. Nallusamy

Nanotechnology has become one of the fastest growing scientific and engineering disciplines. Nano fluids have been established to possess enhanced thermal and physical properties such as thermal conductivity, thermal diffusivity, viscosity and convective heat transfer coefficients. The aim of this research article is to analyze the overall heat transfer coefficient by doing an experimental investigation on the convective heat transfer and flow characteristics of a nano fluid. In this research, an attempt was made for the nano fluid consisting of water and 1% volume concentration of Al2O3/water Nano fluid flowing in a parallel flow, counter flow in shell and tube heat exchanger under laminar flow condition. The 50nm diameter Al2O3nanoparticles are used in this investigation and was found that the overall heat transfer coefficient and convective heat transfer coefficient of nano fluid to be slightly higher than that of the base liquid at same mass flow rate and inlet temperature. Three samples of dissimilar mass flow rates have been identified for conducting the experiments and their results are continuously monitored and reported. The experimental analysis results were concluded that the heat transfer and overall heat transfer coefficient enhancement is possible with increase in the mass flow rate of fluid and Al2O3/water nano fluid on a comparative basis.


Author(s):  
S. V. Sridhar ◽  
R. Karuppasamy ◽  
G. D. Sivakumar

Abstract In this investigation, the performance of the shell and tube heat exchanger operated with tin nanoparticles-water (SnO2-W) and silver nanoparticles-water (Ag-W) nanofluids was experimentally analyzed. SnO2-W and Ag-W nanofluids were prepared without any surface medication of nanoparticles. The effects of volume concentrations of nanoparticles on thermal conductivity, viscosity, heat transfer coefficient, fiction factor, Nusselt number, and pressure drop were analyzed. The results showed that thermal conductivity of nanofluids increased by 29% and 39% while adding 0.1 wt% of SnO2 and Ag nanoparticles, respectively, due to the unique intrinsic property of the nanoparticles. Further, the convective heat transfer coefficient was enhanced because of improvement of thermal conductivity of the two phase mixture and friction factor increased due to the increases of viscosity and density of nanofluids. Moreover, Ag nanofluid showed superior pressure drop compared to SnO2 nanofluid owing to the improvement of thermophysical properties of nanofluid.


2015 ◽  
Vol 62 (4) ◽  
pp. 509-522 ◽  
Author(s):  
R. Dharmalingam ◽  
K.K. Sivagnanaprabhu ◽  
J. Yogaraja ◽  
S. Gunasekaran ◽  
R. Mohan

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.


Author(s):  
Fadi A. Ghaith ◽  
Ahmed S. Izhar

This paper aims to enhance the thermal performance of an industrial shell-and-tube heat exchanger utilized for the purpose of cooling raw natural gas by means of mixture of Sales gas. The main objective of this work is to provide an optimum and reliable thermal design of a single-shelled finned tubes heat exchanger to replace the existing two- shell and tube heat exchanger due to the space limitations in the plant. A comprehensive thermal model was developed using the effectiveness-NTU method. The shell-side and tube-side overall heat transfer coefficient were determined using Bell-Delaware method and Dittus-Boelter correlation, respectively. The obtained results showed that the required area to provide a thermal duty of 1.4 MW is about 1132 m2 with tube-side and shell-side heat transfer coefficients of 950 W/m2K and 495 W/m2K, respectively. In order to verify the obtained results generated from the mathematical model, a numerical study was carried out using HTRI software which showed a good match in terms of the heat transfer area and the tube-side heat transfer coefficient.


Author(s):  
Paritosh Singh

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


2019 ◽  
Vol 64 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Abhishek Lanjewar ◽  
Bharat Bhanvase ◽  
Divya Barai ◽  
Shivani Chawhan ◽  
Shirish Sonawane

In this study, investigation of convective heat transfer enhancement with the use of CuO–Polyaniline (CuO–PANI) nanocomposite basednanofluid inside vertical helically coiled tube heat exchanger was carried out experimentally. In these experiments, the effects of different parameters such as Reynolds number and volume % of CuO–PANI nanocomposite in nanofluid on the heat transfer coefficient of base fluid have been studied. In order to study the effect of CuO–PANI nanocomposite based nanofluid on heat transfer, CuO nanoparticles loaded in PANI were synthesized in the presence of ultrasound assisted environment at different loading concentration of CuO nanoparticles (1, 3 and 5 wt.%). Then the nanofluids were prepared at different concentrations of CuO–PANI nanocomposite using water as a base fluid. The 1 wt.% CuO–PANI nanocomposite was selected for the heat transfer study for nanofluid concentration in the range of 0.05 to 0.3 volume % and Reynolds number range of was 1080 to 2160 (±5). Around 37 % enhancement in the heat transfer coefficient was observed for 0.2 volume % of 1 wt.% CuO–PANI nanocomposite in the base fluid. In addition, significant enhancement in the heat transfer coefficient was observed with an increase in the Reynolds number and percentage loading of CuO nanoparticle in Polyaniline (PANI).


Author(s):  
Guidong Chen ◽  
Jing Xu ◽  
Ming Zen ◽  
Qiuwang Wang

In order to improve heat transfer performance of conventional segmental baffled shell-and-tube heat exchangers (STHXs), the shell-and-tube heat exchanger with combined helical baffles (CMH-STHX) were invented. In the present study, the CMH-STHX is compared with three other STHXs which were set up with continuous helical baffles (CH-STHX), discontinuous helical baffles (DCH-STHX) and segmental baffles (SG-STHX), by Computational Fluid Dynamics method. The numerical results show that, for the same mass flow rate at the shell side, the overall pressure drop of the CMH-STHX is about 50% and 40% lower than that of SG-STHX and CH-STHX. The heat transfer coefficient of the CMH-STHX is between those of CH-STHX and DCH-STHX and it is 6.3% lower than that of SG-STHX. The heat transfer coefficient under unit pressure drop h/Δp is introduced to evaluate the comprehensive performance of STHXs. The h/Δp of the CMH-STHX is 7.5%, 6.5% and 87.4% higher on average than those of the CH-SHTX, DCH-STHX and SG-STHX. Furthermore, the total heat transfer rate of CMH-STHX is about 25% higher than that of SG-STHX for the same total pressure drop of shell side. Supported by these results, the new heat exchanger (CMH-STHX) may be used to replace the conventional shell-and-tube heat exchanger in industrial applications.


Sign in / Sign up

Export Citation Format

Share Document