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 Heat Transfer Performance of EG-Water Based Fe3O4 and its Hybrid Nanofluids in a Double Pipe Heat Exchanger

2019 ◽  
Vol 8 (4) ◽  
pp. 5892-5898
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Base Fluid ◽  
Heat Transfer Performance ◽  
Hybrid Nanofluid ◽  
Transfer Performance ◽  
Overall Performance ◽  
Double Pipe ◽  
Pipe Heat ◽  
Better Than

Nanofluids have good potential in enhancing the heat transfer performance of conventional fluids. In the present paper, the heat transfer performance of Fe3O4 and its Hybrid mixture with Fe3O4 and SiC nanoparticles in the volume ratio of 50:50 in 20:80 Ethylene Glycol (EG) –Water as base fluid are determined experimentally and the results are compared with that of the base fluid. The volume concentration range of nanoparticles considered in the analysis is 0.01% to 0.08%. The experiment is carried under turbulent flow conditions with Reynolds number ranging from 5000 to 20000 in a Double Pipe Heat Exchanger (DPHE) with U-bend. Results indicate that the thermal conductivity of hybrid nanofluid is higher by 16.19% and its viscosity is lower by 11.6% compared to Fe3O4 /20:80 EG-Water nanofluid at an operating temperature of 45°C. The heat transfer coefficient and overall performance of hybrid nanofluid are better than Fe3O4 /20:80 EG-Water nanofluid. The overall performance of Hybrid nanofluid is 27.75% better than that of Fe3O4 /20:80 EG-Water nanofluid.

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 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.

Effect of Using MgO-Oil Nanofluid on the Performance of a Counter-Flow Double Pipe Heat Exchanger

2019 ◽  
Vol 801 ◽  
pp. 193-198 ◽  
Author(s):  
Abdallah Yousef Mohammed Ali ◽  
Ahmed H. El-Shazly ◽  
M.F. El-Kady ◽  
Hesham Ibrahim Fathi ◽  
Mohamed R. El-Marghany
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Base Fluid ◽  
Cold Water ◽  
Corn Oil ◽  
Positive Impact ◽  
Counter Flow ◽  
Inlet Flow ◽  
Double Pipe ◽  
Pipe Heat

In the present study, heat transfer characteristics of MgO-oil based nanofluid in a miniature counter-flow double-pipe heat exchanger are investigated experimentally and numerically. The nanofluid is a mixture of corn oil as a base fluid and MgO particles in nanorange. The heat exchanger is fabricated from 316 stainless steel with length 500 mm. Cold water flows in the annulus side, and the nanofluid is utilized as the hot medium in the inner tube. ANSYS FLUENT 17,0 commercial software was employed for numerical investigation. The results obtained from using nanofluids are compared with the pure oil base fluid as a hot medium. Effects of inlet flow rate of hot nanofluids and concentration of nanoparticles are considered. It is observed that the average heat transfer rates for nanofluids are higher than those for pure corn oil. The improvement of both MgO concentration and inlet flow rates of nanofluid has a positive impact on the overall heat transfer coefficient and heat transfer rate. In contrast, the pumping power augments as well as the pressure drop increases.

scholarly journals Study the Effect of Granules Type of The Porous Medium on The Heat Transfer Enhancement for Double Pipe Heat Exchanger

2019 ◽  
Vol 26 (4) ◽  
pp. 43-49
Author(s):  
Ehsan Abbas ◽  
Shagul Mohammed
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Exchanger ◽  
Cold Water ◽  
Hot Water ◽  
Transfer Enhancement ◽  
Copper Pipe ◽  
Inner Diameter ◽  
Double Pipe ◽  
Pipe Heat

The current study includes the effect of the type of porous medium on the heat transfer enhancement for double-pipe heat exchanger. Using the three types of the porous medium of balls (steel, ceramic and glass) with diameters (6.35, 6 and 7) mm respectively. The tests were carried out on a locally manufactured heat exchanger, consisting of a copper pipe with an inner diameter (20mm), an outer diameter (22mm) and a length of (1800mm), fixed inside a pipe made of galvanized iron with the same length of copper pipe with inner diameter (50mm) and thickness (5mm). The heat exchanger is insulated with a layer of glass wool to prevent leakage of heat to the area surrounding the exchanger. The tests carried out on the heat exchanger in four cases, the three cases for porous medium, also the case of exchanger without porous medium, and for all cases identical operating conditions, which is inlet temperature of hot, and cold water determined at (63 and 32)˚C and the number of Reynolds from (1100 to 9750) for cold water and (415 to 7500) for hot water. The experimental results showed that the highest thermal conductivity was obtained when the ceramic balls were used, which was estimated to be approximately (219.302) W/˚C and increased by (105.3%, 10.8%, 4.3%) for cases: without porous medium, glass balls and steel balls respectively. The effect of the pressure drop in the hot water side, was recorded the highest value for pressure drop when the ceramic balls were used and ranged from (0.5 to 19.5) mmHg and increased by (0.95%, 2.25%) when compared with the results of two cases for balls (steel and glass) respectively.

scholarly journals Numerical investigation on enhancement of heat transfer using rod inserts in single pipe heat exchanger

2019 ◽  
Vol 13 (4) ◽  
pp. 6112-6124
Author(s):  
M. A. Ashham ◽  
S. H. Raheemah ◽  
K. Salman
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Evaluation Criteria ◽  
Enhancement Of Heat Transfer ◽  
Slant Angle ◽  
Double Pipe ◽  
Single Pipe ◽  
Pitch Distance ◽  
Pipe Heat

The current study focused on statistically investigating nanofluids’ turbulent flow and rate of heat transfer in double pipe heat exchanger with rod inserts. Through the use of numerical simulation, the effects which the various kinds of nanofluids have on the enhancement of heat transfer using finite volume method (FVM) are studied. An application of homogeneous heat flux is made to the tube wall. More so, an examination of the effect of three varying slant angles of rod insert (α = 25°, 30°, 45°) was carried out at varying Reynolds number ranging from 7500 - 20000. The statistical results revealed that the coefficient of transferring heat in the tube containing rod inserts is higher than that of the smooth tube. In addition, results also showed that when rod insert are used in double pipe heat exchanger to augment the Nusselt number increases the slant angle. The max value of Nusselt number was demonstrated at the angle 45° of rod insert. Through the use of the rod inserts at (α=45°) and (S = 30mm), the coefficient of maximal skin friction was determined because of the resistance of larger flow. The maximal value of the Performance Evaluation Criteria (PEC) was mentioned in the case of min slant angle of (α = 25°) and the pitch distance of S = 30 mm.

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