OPTIMIZATION OF HEAT TRANSFER RATE ON A DOUBLE PIPE HEAT EXCHANGER USING CFD

2021 ◽  
Vol 34 (02) ◽  
Author(s):  
Mohammad Sikindar Baba ◽  
◽  
Oddarapu Kalyani ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Double Pipe ◽  
Pipe Heat

scholarly journals FIBERGLASS CIRCULAR TURBULATOR IN COUNTER FLOW DOUBLE PIPE HEAT EXCHANGER: A STUDY OF HEAT TRANSFER RATE AND PRESSURE DROP

SINERGI ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 51
Author(s):  
Sudiono Sudiono ◽  
Rita Sundari ◽  
Rini Anggraini
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Preliminary Investigation ◽  
Working Fluid ◽  
Geometrical Shape ◽  
Double Pipe ◽  
Pipe Heat

This preliminary investigation studied the effect of circular turbulator vortex generator on heat transfer rate and pressure drop in a circular channel countercurrent double pipe heat exchanger with water working fluid. Increasing the number of circular turbulator yielded increasing heat transfer rate and pressure drop. The problem generated when increased pressure drop occurred in relation to more energy consumption of the water pumping system. Therefore, optimization in circular turbulator number is necessary to minimize the pressure drop about distance length between circular turbulator, tube diameter and thickness, type of material and crystal lattice, as well as the geometrical shape of fluid passage (circular or square). This study applied PVC outer tube and copper alloy inner tube, as well as fiberglass circular turbulator. The optimum results showed that seven parts of circular turbulator increasing heat transfer rate by 30% and pressure drop by 80% compared to that passage in the absence of circular turbulator at cool water debit of 7 L/min.

scholarly journals A Numerical Simulation Study to Improve Heat Transfer Rate in a Double Pipe Heat Exchanger using Different ways.

2021 ◽  
Vol 1973 (1) ◽  
pp. 012113
Author(s):  
Zomorrod Ahmed Salman ◽  
Zena Khalefa Kadhim ◽  
Kamil Abdulhussein khalaf ◽  
Hassanein Ali Kamil
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Simulation Study ◽  
Transfer Rate ◽  
Improve Heat Transfer ◽  
Double Pipe ◽  
Pipe Heat

Reliable Method of a Non-Insulated Double-Pipe Heat Exchanger

2013 ◽  
Vol 284-287 ◽  
pp. 908-914
Author(s):  
King Leung Wong ◽  
Wen Lih Chen ◽  
Li Wen Po
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Total Heat ◽  
Heat Radiation ◽  
Total Heat Transfer ◽  
Double Pipe ◽  
Single Pipe ◽  
Pipe Heat

Log mean temperature difference (LMTD) method neglecting the influence of heat radiation is conventionally used to calculate the total heat transfer rate of heat exchangers. From recent investigation of a single-pipe heat exchanger in some practical situations, it is found that the total heat transfer rate error of single-pipe heat exchanger obtained by LMTD method is up to 40% in the situation of oxidized metal heat exchanger with higher surface emissivity located in ambient air with low heat convection coefficient. A log mean heat transfer rate (LMHTR) method considering heat radiation has been developed to calculate the total heat transfer rate of a single-pipe heat exchanger and more accurate results can be achieved. It is also found in the present investigation that LMTD method is also not suitable to apply to non-insulated double-pipe heat exchangers and a more accurate LMHTR method considering heat radiation is developed to obtain the more reasonable results.

Performance of Phase Change Materials in a Horizontal Annulus of a Double-Pipe Heat Exchanger in a Water-Circulating Loop

2006 ◽  
Vol 129 (3) ◽  
pp. 265-272 ◽  
Author(s):  
J. R. Balikowski ◽  
J. C. Mollendorf
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Phase Change ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Phase Change Materials ◽  
Water Flows ◽  
Double Pipe ◽  
Pipe Heat

Phase change materials (PCMs) are used in applications where temperature regulation is important because they absorb and release a large amount of energy at a fixed temperature. In the experimental part of this investigation, PCM was placed in the annular region of a double-pipe heat exchanger with water circulated in the inside pipe. Experiments were performed in which the PCM would absorb (charge) and then release (discharge) energy at various temperatures and water flows. Two materials, Climsel 28 (C28) by Climator and microencapsulated Thermasorb 83 (TY83) by Outlast Technologies, were each tested in smooth and spined annuli to observe which configuration facilitated heat transfer. The latent heats and thermal conductivities of C28 and TY83 are 126kJ∕kg and 186kJ∕kg and 0.6W∕m∕°C and 0.15W∕m∕°C, respectively. The experimental data were analyzed to verify which PCM transferred more heat. The effect of different water flow rates on the heat transfer rate was also examined. In the theoretical part of this investigation, heat transfer theory was applied to C28 in the smooth-piped heat exchanger in order to better understand the phase change process. The presence of spined fins in the phase change material accelerated charging and discharging due to increased fin contact with the outer layers of the PCM. The spined heat exchanger charged and discharged in 180min and 120min, respectively, whereas the temperature in the smooth heat exchanger remained below the fully charged/fully discharged asymptote by about 3°C and thus failed to fully charge or fully discharge. Also, higher water flows increased heat transfer between the PCM and water. TY83 in the spined heat exchanger transferred more heat and did it faster than C28 in the spined heat exchanger. The heat transfer rate from the water to TY83 while charging was 25% greater during the transient period than in C28. While discharging, the heat transfer from TY83 to the water was about 20% greater than in C28. There was generally good agreement (±1.5°C) between theory and experimental data of C28 in the smooth-piped heat exchanger in terms of the trends of the temperature responses. The differences are expected to be a result of approximations in boundary conditions and uncertainties in how the temperature variation of the specific heat is formulated.

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 Design and analysis of double-pipe heat exchanger using both helical and rotating inner pipe

2021 ◽  
Vol 25 (2 Part B) ◽  
pp. 1545-1559
Author(s):  
Tarkan Koca ◽  
Aydın Citlak
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cold Water ◽  
Straight Tube ◽  
Empirical Formulas ◽  
Pressure Losses ◽  
Annular Gap ◽  
Double Pipe

In this study, the effects of rotating straight and helical inner tubes is experimentally discussed to determine heat transfer and pressure losses in rotating tubes and improve heat transfer. The outer tube remains stationary and the inner tube is rotated at different speeds in the work. In the experiments for straight and helical tubes, the flow regime is turbulent. According to the results, Nusselt number, pressure loss, and efficiency of heat exchanger were gauged. In addition, empirical formulas were obtained for each pipe type. It is observed that as the rotation speed of the pipe increases, the heat transfer rate increases. The pipe that provides the best increase in heat transfer is the five helixes tubes. At five helixes tubes; after the number of revolutions per minute exceeds 300, the increase in heat transfer rate has almost halt. At five helixes tubes and at 300 rpm speed when the flow of cold water through the annular gap with the fluid passing through the inner tube is equal, the heat transfer increases by 124.10% compared to straight tube, 23.47% compared to two helixes tubes, 7.92% compared to three helixes tubes, and 1.65% compared to four helixes tubes. Maximum effectiveness was obtained while rotating with 300 rpm in five helixes pipes.

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