scholarly journals Experimental and CFD Analysis of GW70 based Cu Nanofluids in a Parallel Flow Heat Exchanger

2021 ◽  
Vol 10 (4) ◽  
pp. 106-110
Author(s):  
M.L.R. Chaitanya Lahari ◽  
◽  
P.H.V. Sesha Talpa Sai ◽  
K.V. Sharma ◽  
K.S. Narayanaswamy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Parallel Flow ◽  
Hot Water ◽  
Cfd Analysis ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Double Pipe ◽  
Pipe Heat

The Nusselt number, overall heat transfer, and convective heat transfer coefficients of glycerol-water-based Cu nanofluids flowing in a parallel flow double pipe heat exchanger are estimated using CFD analysis. Single-phase fluid approach technique is used in the analysis. Ansys 19.0 workbench was used to create the heat exchanger model. Heat transfer tests with nanofluids at three flow rates (680<Re<1900) are carried out in a laminar developing flow zone. For testing, a 500 mm long concentric double pipe heat exchanger with tube dimensions of ID=10.2 mm, OD= 12.7 mm, and annulus dimensions of ID=17.0 mm, OD= 19.5 mm is employed. Copper is utilized for the tube and annulus material. This study employed three-particle volume concentrations of 0.2 percent, 0.6 percent, and 1.0 percent. The mass flow rates of hot water in the tube are 0.2, 0.017, and 0.0085 kg/s, while the mass flow rates of nanofluids in the annulus are 0.03, 0.0255, and 0.017 kg/s. The average temperature of nanofluids is 36°C, whereas hot water is 58°C. In comparison to base liquid, the overall heat transfer coefficient and convective HTC of 1.0 percent copper nanofluids at 0.03 kg/s are raised by 26.2 and 46.2 percent, respectively. The experimental findings are compared to CFD values, and they are in close agreement.

scholarly journals Numerical Analysis of Heat transfer Enhancement in a double pipe heat exchanger with a holed twisted tape

2018 ◽  
Vol 144 ◽  
pp. 04012
Author(s):  
Akarsh Kumar ◽  
Ujjawal Sureka ◽  
Shiva Kumar
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Transfer Rate ◽  
Twisted Tape ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Double Pipe ◽  
Pipe Heat

In the present study numerical analysis of enhancement in heat transfer characteristics in a double pipe heat exchanger is studied using a holed twisted tape.The twisted tape with a constant twist ratio is inserted in a double pipe heat exchanger. Holes of diameter 1mm, 3 mm and 5 mm were drilled at regular pitch throughout the length of the tape. Numerical modeling of a double pipe heat exchanger with the holed twisted tape was constructed considering hot fluid flowing in the inner pipe and cold fluid through the annulus.Simulation was done for varied mass flow rates of hot fluid in the turbulent condition keeping the mass flow rate of cold fluid being constant. Thermal properties like Outlet temperatures, Nusselt number, overall heat transfer coefficient, heat transfer rate and pressure drop were determined for all the cases. Results indicated that normaltwisted tape without holes performed better than the bare tube. In the tested range of mass flow rates the average Nusselt number and heat transfer rate were increased by 85% and 34% respectively. Performance of Twisted tape with holes was slightly reduced than the normal twisted tape and it deteriorated further for higher values hole diameter. Pressure drop was found to be higher for the holed twisted tape than the normal tape.

scholarly journals Pengaruh Pitch Turbulator Terhadap Ntu Pada Double Pipe Heat Exchanger

2019 ◽  
Vol 3 (1) ◽  
pp. 27
Author(s):  
Mufid Mufid ◽  
Arif Rahman Hakim ◽  
Bambang Widiono
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Heat Exchanger ◽  
Transfer Rate ◽  
Cold Water ◽  
Hot Water ◽  
Energy Sources ◽  
Energy Needs ◽  
Double Pipe ◽  
Pipe Heat

Saat ini kebutuhan akan energi di dunia terus meningkat, sejalan dengan semakin tumbuhnya industri untuk menopang kehidupan manusia. Namun kenaikan kebutuhan energi tersebut tidak diimbangi dengan bertambahnya sumber energi, sehingga harga energi semakin mahal. Untuk meminimalisir kebutuhan energi, maka perlu dicari sumber-sumber energi alternatif baru, terutama sumber energi baru dan terbarukan. Disamping itu perlu dilakukan pengelolaan energi yang lebih baik, sehingga kebutuhan energi dunia bisa dikurangi. Double Pipe Heat exchanger memiliki pipa luar stainless steel dengan diameter dalam (Do) 3,5 inchi, ketebalan pipa (To) 1,5 mm, dan panjang pipa (Lo)  790mm dan pipa dalam (Di) 1 3/8 inchi,   ketebalan(Ti) 0,6 mm, dan panjang pipa (Li) 920mm, dengan air dingin dan air panas yang digunakan sebagai fluida uji di annulus dan pipa dalam. Helical turbulator dari besi (mild steel) dengan dimensi geometris jarak antar elemen (pitch) sebesar 25mm, 50 mm dan 75 mm berdiameter dalam (Di) 5/16 inchi dan diameter luar(Do) 1 5/16 inchi dengan panjang 750mm dimasukkan dalam inner tube dari heat exchanger. Air panas memasuki tabung dengan variasi flowate mulai  400 l/jam sampai 900 l/jam, sedangkan flowrate air dingin konstan 900 l/jam. Hasil penelitian dengan  disisipkannya helical turbulator   sebagai turbulator pada heat exchanger mengakibatkan peningkatan laju perpindahan kalor. Helical turbulator dengan pitch 25mm menimbulkan peningkatan laju perpindahan kalor  paling besar sebesar ±62% dibandingkan plain tube. Helical turbulator mengakibatkan peningkatan NTU heat exchanger terbesar sebesar ±63% dihasilkan oleh helical turbulator dengan pitch 25mm.At present the need for energy in the world continues to increase, in line with the growing industry to sustain human life. However, the increase in energy needs is not offset by the increase in energy sources, so energy prices are increasingly expensive. To minimize energy needs, it is necessary to look for new alternative energy sources, especially new and renewable energy sources. Besides that, better energy management is needed, so that the world's energy needs can be reduced. Double Pipe Heat Exchanger has stainless steel outer pipe with inner diameter (Do) 3.5 inch, pipe thickness (To) 1.5 mm, and pipe length (Lo) 790 mm and pipe inside (Di) 1 3/8 inch, thickness (Ti) 0.6 mm, and the length of pipe (Li) 920 mm, with cold water and hot water used as test fluid in the annulus and inner pipe. Mild steel helical turbulators with geometric dimensions of 25mm, 50mm and 75mm intervals between 5/16 inch in diameter and a 750mm length 5/16 inch outer diameter (Do) are included in the inner tube of heat exchanger. Hot water enters the tube with variations in flowate from 400 l / hour to 900 l / hour, while the cold water flowrate is constant 900 l / hour. The results of the study by inserting a helical turbulator as a turbulator in a heat exchanger resulted in an increase in the heat transfer rate. Helical turbulators with a pitch of 25mm give rise to the highest heat transfer rate of ±62% compared to plain tubes. Helical turbulators cause the largest increase in NTU heat exchanger of ±63% produced by a helical turbulator with a 25mm pitch.

scholarly journals ENHANCEMENT OF HEAT TRANSFER IN DOUBLE PIPE HEAT EXCHANGER USING AL2O3-FE2O3/WATER HYBRID NANOFLUID

2021 ◽  
Vol 21 (2) ◽  
pp. 148-163
Author(s):  
Mawj K. Qasim ◽  
Hadi O. Basher ◽  
Mohammed D. Salman
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Friction Coefficient ◽  
Base Fluid ◽  
Hot Water ◽  
Hybrid Nanofluid ◽  
Fe2o3 Nanoparticles ◽  
Enhancement Of Heat Transfer ◽  
Double Pipe ◽  
Pipe Heat

This study aims to enhancement of heat transfer in double pipe heat exchanger by improving the thermal properties of base fluid which is water by adding AL2O3-Fe2O3 nanoparticles to the water. Al2O3-Fe2O3/water hybrid Nanofluid were examined experimentally and numerically at different flow rates ranging between (3 -7) Lpm at temperature of 25°C in an external tube while there was a hot water at a temperature of 60°C and a flow rate ranged between (3 – 5) Lpm running in the central tube of a double pipe counter heat exchanger. Also, the effect of various concentrations ranged between (0.05, 0.1, 0.15, 0.2, 0.25 and 0.3%) of Al2O3-Fe2O3 nanoparticles dispersed in water on the rate of heat transfer, friction coefficient were verified experimentally and numerically . The ratio of Al2O3-Fe2O3 is 0.5:0.5. The experimental and numerical study indicated that with the rate of heat transfer increases when the concentration of suspended nanoparticles in the base fluid increases , but on the other hand, the skin friction coefficient and pressure drop increases as well with increasing the concentration of nanoparticles. The maximum enhancement in heat transfer for AL2O3-Fe2O3 is about 6 % . The results from the experimental study were largely consistent with the numerical results.

scholarly journals Improving thermal performance using Al2O3-water nanofluid in a double pipe heat exchanger filling with porous medium

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4267-4275
Author(s):  
Qusay Jasim ◽  
Noah Saleh ◽  
Adnan Hussein
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Volume Flow ◽  
Inlet Temperature ◽  
Flow Rates ◽  
Inside Diameter ◽  
Double Pipe ◽  
Pipe Heat

A double pipe heat exchanger is significant device for many industrial applications. In this paper, an experimental study using both porous media and nanofluid to enhance heat transfer in a double pipe heat exchanger is performed. The test rig has been fabricated with inner copper pipe of 1.10 m length, 16 mm, and 14 mm outside and inside diameter, respectively. While, the outer PVC pipe is 1 m length, 31 mm, and 27 mm outside and inside diameter, respectively. The inner pipe has been filling with 3 mm diameters of steel balls porous media. The experimental tests were performed utilizing alumina nanofluid (Al2O3-water) with two volume concentrations 0.5% and 1%. The volume flow-rates are in the range of (2-5) Lpm and 10 Lpm through inner and outer pipe, respectively. It was conducted with a constant 28?C inlet temperature of cold fluid-flow inside the inner pipe and 50?C inlet temperature of hot fluid-flow inside the outer pipe. Results indicated that the heat transfer enhanced as nanofluid volume concentrations and volume flow-rates increase. It was observed that effectiveness increases as increase of flow-rate and nanofluid concentrations.

Performance Analysis of Shell and Tube Heat Exchanger using Different Nanofluids

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
J. Thavamani
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Base Fluid ◽  
Particle Diameter ◽  
Flow Rates ◽  
Tube Heat Exchanger ◽  
Cold Fluid ◽  
Mass Flow Rates ◽  
Shell And Tube

Heat exchanger is the most important function in industrial sector for transferring heat energy to useful work. Heat transfer occurs between the cold fluid and hot fluid or from hot fluid to cold fluid in conduction and convection mode of through a heat exchanger wall. If heat transfer medium has very low thermal conductivity, it would have limited the efficiency of heat exchanger. Whenever the system is subjected to increased heat load, cooling is the main technical challenge for industries. The main objective of this work is to evaluate the effectiveness of shell and tube heat exchanger experimentally and analyse the flow behaviours of different nanofluids. In our experimental analysis, various nanofluids which consist of water and one percentage volume concentration of Al2O3, CuO and SiO2 passing through tube side in the shell and tube heat exchanger. The nano particle diameter is 70nm. The three dissimilar mass flow rates are considered for the experiments and their results are continuously monitored. The enhancement of heat transfer performance of CuO, Al2O3, SiO2 is compared with the base fluid water. Reynolds number values are calculated with three different mass flow rates and compared with heat transfer characteristics (LMTD, Nusselt number and overall heat transfer coefficient). SEM analysis, energy dispersive spectroscopy, X-ray diffraction of CuO, Al2O3 and SiO2.are conducted. The heat transfer effectiveness is increased by 22.12%, 19.46% and 1.47% respectively for CuO, Al2O3 and SiO2 when compared to base fluid.

Shell and tube heat exchanger thermal-hydraulic analysis equipped with baffles and corrugated tubes filled with non-Newtonian two-phase nanofluid

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Akbar Abbasian Arani ◽  
Reza Moradi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mass Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Content Type ◽  
Mass Flow Rates ◽  
Shell And Tube

Purpose Using turbulators, obstacles, ribs, corrugations, baffles and different tube geometry, and also various arrangements of these components have a noticeable effect on the shell and tube heat exchangers (STHEs) thermal-hydraulic performance. This study aims to investigate non-Newtonian fluid flow characteristics and heat transfer features of water and carboxyl methyl cellulose (H2O 99.5%:0.5% CMC)-based Al2O3 nanofluid inside the STHE equipped with corrugated tubes and baffles using two-phase mixture model. Design/methodology/approach Five different corrugated tubes and two baffle shapes are studied numerically using finite volume method based on SIMPLEC algorithm using ANSYS-Fluent software. Findings Based on the obtained results, it is shown that for low-mass flow rates, the disk baffle (DB) has more heat transfer coefficient than that of segmental baffle (SB) configuration, while for mass flow rate more than 1 kg/s, using the SB leads to more heat transfer coefficient than that of DB configuration. Using the DB leads to higher thermal-hydraulic performance evaluation criteria (THPEC) than that of SB configuration in heat exchanger. The THPEC values are between 1.32 and 1.45. Originality/value Using inner, outer or inner/outer corrugations (outer circular rib and inner circular rib [OCR+ICR]) tubes for all mass flow rates can increase the THPEC significantly. Based on the present study, STHE with DB and OCR+ICR tubes configuration filled with water/CMC/Al2O3 with f = 1.5% and dnp = 100 nm is the optimum configuration. The value of THPEC in referred case was 1.73, while for outer corrugations and inner smooth, this value is between 1.34 and 1.57, and for outer smooth and inner corrugations, this value is between 1.33 and 1.52.

scholarly journals EXPERIMENTAL STUDY OF HEAT TRANFER AUGMENTATION USING AIR BUBBLE INJECTION AND (Al2O3 /WATER) NANOFLUID FLOW IN DOUBLE PIPE HEAT EXCHANGERS

2021 ◽  
Vol 21 (2) ◽  
pp. 96-117
Author(s):  
Dhirgham A. Alkhafaji ◽  
Hameed K. Hamzah ◽  
Haider S. Hadi
Keyword(s):  
Heat Transfer ◽  
Cold Water ◽  
Volume Flow ◽  
Hot Water ◽  
Air Bubbles ◽  
Heat Transfer Characteristics ◽  
Flow Rates ◽  
Air Bubble ◽  
Double Pipe ◽  
Pipe Heat

In the present work, an experimental study on how to increase the heat transfer coefficient (HTC) in double pipe heat exchanger (DPHE) use of a variety of Al2O3 Nano-dispersion concentrations mixed in water as base fluid with air bubble injection for counter flow arrangement under turbulent flow conditions with (Re) Reynold number range from (6000 t0 45000) . The thermal performance of (DPHE) has been enhanced with the use of two techniques. The first, is represented by adding nanoparticles to hot water (inner pipe) raising the (HTC) inside the inner tube. Increase the volume concentration cause increase in the viscosity of the nanofluid leading to increase in friction factor .Secondly is represented by Air bubble injection in outer pipe with cold water to enhance the (HTC). The mobility of air bubbles inside the water from down to up by the force of the buoyancy, and the movement of these air bubbles results in significant mixture and turbulence within the water. The variations of number of thermal units (NTU), exergy loss, dimensionless exergy and (Nu) are evaluated. The investigated parameters were cold water volume flow rates (8, 10, 12 and14) l/min, flow in outer tube. Also, three different volume flow rates of air (12, 16 and 20) l/min mixed with water in outer tube. The volume flow rates of hot water remains constant at (8 l/min) flow in inner pipe with three volumetric concentrations of given nanofluid. The results showed that the air bubble injection throughout the tube gave maximum enhancement in heat transfer characteristics followed by the no air bubble injection. Since the enhancement in heat transfer characteristics varies linearly with the volumetric concentration of Nanofluids, Nanofluids with 0.3% of Al2O3 nanoparticles gave more enhancements in (HTC) than the case without nanofluid. The Nusselt number increased about (8% - 45%).  

Applications of Performance Tables on Steady State Analysis of Multipass Parallel Cross Flow Heat Exchanger

2017 ◽  
Vol 28 ◽  
pp. 53-72
Author(s):  
Karthik Silaipillayarputhur ◽  
Ali Al-Saif ◽  
Musab Al-Otaibi
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Thermal Performance ◽  
Rate Ratio ◽  
Cross Flow ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Operational Phase

In this paper, steady state sensible performance analysis on multi pass parallel cross flow exchanger was considered. The inputs to the heat exchanger were described through meaningful physically significant parameters such as number of transfer units, capacity rate ratio and dimensionless input temperature. The inputs to the heat exchager were varied systematically and a parametric study was conducted to determine the thermal performance at each individual pass of the heat exchanger. Heat exchanger’s thermal performance was described through the discharge temperatures that were expressed in a dimensionless form. The results from the study were presented in the form of performance tables. The performance tables employed meaningful and industry recognized dimensionless input parameters and the heat exchanger‘s performance was described through dimensionless discharge temperatures at every pass of the heat exchanger. The developed performance tables shall serve two critical aspects. First, it will help the heat exchanger designers to readily choose an optimum heat exchanger. An undersized heat exchanger shall not deliver the requirements and likewise an oversized heat exchanger shall add unnecessary weight and cost. This aspect was clearly observed in this study as indefinetly increasing the number of transfer units (or surface area) beyond a threshold value didn’t enhance the heat transfer. By employing the performance tables as a guide, the heat exchanger designers can quickly ascertain the performance of the heat exchanger without having to perform simulations and/or lengthy calculations. Second, during operational phase of the heat exchanger, the performance tables can be used to understand the performance variation of the heat exchanger with respect to mass flow rates and/or can help the engineers to choose appropriate mass flow rates for the required heat transfer. The highest heat exchanger performance was observed at the lowest capacity rate ratio and likewise the lowest heat exchanger performance was observed at the highest capacity rate ratio. In-addition, during the operational phase, the performance tables can help to detect an underperforming heat exchanger and can help the engineers to schedule maintenance activity on the heat exchanger equipment.

Investigating the effect of nanoparticle on thermo-economic optimization of fin and tube heat exchanger

2016 ◽  
Vol 231 (6) ◽  
pp. 1127-1140 ◽  
Author(s):  
Hassan Hajabdollahi ◽  
Zahra Hajabdollahi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Mass Flow ◽  
Annual Cost ◽  
Design Parameters ◽  
Total Annual Cost ◽  
Cold Side ◽  
Flow Rates ◽  
Tube Heat Exchanger ◽  
Mass Flow Rates

In this paper, the effects of Al2O3 nanoparticles suspended in the water-based fluid on the thermo-economic properties of a fin and tube heat exchanger are studied using fast and elitism nondominated sorting genetic algorithm. Nine design parameters are selected as design parameters, and the total annual cost and effectiveness are considered as the two objective functions. First, the effect of nanoparticle on the total annual cost versus effectiveness is obtained at different cold side mass flow rates, and the results are compared with the base fluid. The results show that nanoparticles have a significant influence on the total annual cost and effectiveness in a lower cold side mass flow rates. Next, the heat exchanger volume versus effectiveness for the optimum points is measured at different cold side mass flow rates. It is demonstrated that, adding Al2O3 nanoparticle to the base fluid for the fixed value of effectiveness, decreases the heat exchanger volume, and this reduction is more significant in the lower mass flow rates. The pressure drop and total heat transfer surface area versus effectiveness for the optimum points are also obtained with and without nanoparticle. An increase in the tube side pressure drop is revealed in the nanofluid. In addition, due to the increase in the overall heat transfer coefficient, the lower heat transfer surface area is required for the fixed value of effectiveness. Finally, variations of objective functions versus particle volumetric concentration for five typical optimum points are estimated. It is concluded that an optimal value for the volumetric concentration can be obtained, in which the effectiveness is highest.

Sign in / Sign up

Export Citation Format

Share Document