scholarly journals Heat transfer Augmentation of Gravity Assisted Multi Heat pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (1S4) ◽  
pp. 648-652
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Cold Water ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Heat Transfer Augmentation ◽  
Acetone Water ◽  
Mass Flow Rates ◽  
Cold Water Temperature

Heat transfer augmentation of a heat exchanger with a multi-heat pipe has been investigated with the influence of gravity assistance. The working fluids used to analyse the performance are methanol and acetone. Water is used as a heat transfer fluid. In which, the analysis is carried out with the gravity-assisted angles of 0º, 45º and 90º. In this work, various parameters such as temperatures of hot water ranges 50ºC, 60ºC, 70ºC, and cold water temperature are observed as 32.5ºC throughout the investigation. Hot water mass flow rates as 40 LPH to 120 LPH with an increase of 20 LPH, cold water as 20 LPH to 60 LPH with an increase of 10 LPH. The result reveals that increase in effectiveness occurs at an angle of 0º for Acetone with 60ºC and 100 LPH is 71.5% of an increase in effectiveness is achieved than methanol for optimum said conditions.

Experimental Investigation of Heat Transfer Enhancement by Using Different Number of Fins in Circular Tube

2018 ◽  
Vol 6 (3) ◽  
pp. 1-12
Author(s):  
Kamil Abdul Hussien
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cold Water ◽  
Finned Tube ◽  
Hot Water ◽  
Copper Tube ◽  
Smooth Tube ◽  
Tube Heat Exchanger ◽  
Mass Flow Rates ◽  
Flow Heat

Abstract-The present work investigates the enhancement of heat transfer by using different number of circular fins (8, 10, 12, 16, and 20) in double tube counter flow heat exchanger experimentally. The fins are made of copper with dimensions 66 mm OD, 22 mm ID and 1 mm thickness. Each fin has three of 14 mm diameter perforations located at 120o from each to another. The fins are fixed on a straight smooth copper tube of 1 m length, 19.9 mm ID and 22.2 mm OD. The tube is inserted inside the insulated PVC tube of 100 mm ID. The cold water is pumped around the finned copper tube, inside the PVC, at mass flow rates range (0.01019 - 0.0219) kg/s. The Reynold's number of hot water ranges (640 - 1921). The experiment results are obtained using six double tube heat exchanger (1 smooth tube and the other 5 are finned one). The results, illustrated that the heat transfer coefficient proportionally with the number of fin. The results also showed that the enhancement ratio of heat transfer for finned tube is higher than for smooth tube with (9.2, 10.2, 11.1, 12.1 13.1) times for number of fins (8, 10, 12, 16 and 20) respectively.

scholarly journals Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (2S2) ◽  
pp. 143-147 ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Hot Water ◽  
Working Fluid ◽  
Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

scholarly journals Thermal Behaviour Analysis of Baffled Multi Heat pipe Induced Heat Exchanger

2019 ◽  
Vol 8 (4S2) ◽  
pp. 275-279
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Thermal Behaviour ◽  
Cold Water ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Compact Heat Exchanger ◽  
Improve Performance ◽  
Flow Rates ◽  
Mass Flow Rates

Thermal behaviour of a multi-heat pipe induced in compact heat exchanger has been analysed with the influence of baffles. The heat transfer fluid and working fluid used for the investigation are water and acetone. In this investigation, baffles are used to improve performance. In this research, different parameters like temperature range of hot and cold water were 50ºC, 60ºC, 70ºC and 32ºC throughout the analysis. The mass flow rates of hot and cold water ranges as 40 LPH to 120 LPH and 20 LPH to 60 LPH with an increase of 20 LPH and 10 LPH. The result shows that for an optimum revealed conditions of an angle of 0º with 60ºC and 100 LPH there is an increase in effectiveness occurs as 82.05% while comparing to without baffled conditions.

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.

Numerical Modeling of Turbulent Heat Transfer and Fluid Flow in a Tunnel Pasteurization Process

1999 ◽  
Author(s):  
Y. H. Zheng ◽  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Cold Water ◽  
Hot Water ◽  
Turbulent Heat Transfer ◽  
Parameter Method ◽  
Turbulent Heat ◽  
Water Tank ◽  
Lumped Parameter

Abstract The purpose of this study is to model the heat transfer and fluid flow in a tunnel pasteurizer, which can be used to predict the operation status of the pasteurization process. This modeling is very useful when some changes must be made to the design, operation, or the types of products to be pasteurized. Moreover, the model can be used to provide valuable data for the optimization of the pasteurization design. In the modeling two approaches have been adopted. One is the Lumped Parameter Method (LPM), which is used to model the whole pasteurization system, including pipes, zones and heat exchangers. The other one is the Computational Fluid Dynamics (CFD) technology for calculations of the heat transfer and fluid flow rates in the heat exchanger tank. A steady state model in a tunnel pasteurizer has been developed by using the LPM. The temperatures of the spray water and the products in the pasteurization process were calculated by employing this model. The comparisons showed reasonably good agreements between the predicted results and the experimental data. The pressure variations along the regenerative loops were also calculated. With the CFD technology, the numerical calculations of heat transfer and fluid flow have been performed on the temperature distribution in the cylindrical heat exchanger tank that provides a hot water through the top and a cold water through the bottom of tank. There are two outlets. In the heat exchanger tank, the tube arrays are set along the azimuth direction of the tank. This is a thermally stratified layered water tank that can control the four zones of the water temperatures.

Computational Investigation of Heat Transfer of Nanofluids in Domestic Water Heat Exchanger

2014 ◽  
Vol 695 ◽  
pp. 423-427
Author(s):  
Nor Azwadi Che Sidik ◽  
Lee Yoke Keen ◽  
Alireza Fazeli
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Base Fluid ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Computational Investigation ◽  
Domestic Water ◽  
Alumina Nanoparticle ◽  
Water Based ◽  
Water Base

Recent development of nanotechnology led to the concept of using suspended nanoparticles in the heat transfer fluids to improve the heat transfer properties of the base fluids. The heat transfer enhancement by nanofluids is the significant concerns in the efficiency of domestic water heat exchanger system. A computational investigation of the heat transfer in a domestic water heat exchanger is conducted on the water and water-based nanofluids. Copper (Cu) nanoparticle and Alumina (Al2O3) nanoparticle are selected in the water-based nanofluids. Volume fraction of nanoparticle in the nanofluids is set at 0.5 %, 1.0 %, 1.5 %, 2.0 %, 2.5 %, and 3.0 %. Heat exchanger has been invented for the heat transfer from one medium to another medium in many heat transfer systems. Domestic water heat exchanger can be used in a heat pump domestic water heating system. The density, the thermal conductivity, and the dynamic viscosity of the water base fluid are increased while the specific heat capacity of the water base fluid is reduced with the addition of copper as well as alumina nanoparticle. Addition of copper nanoparticle into the water-based heat transfer fluid significantly increases the domestic hot water temperature. The efficiency of domestic water heat exchanger system is optimum when 1.5 % copper or alumina nanoparticle is added into the water-based heat transfer fluid.

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 Helical Screw Tape Insertion on Heat Transfer and Pressure Drop Characteristics in a Horizontal Concentric Double Tube Heat Exchanger

2014 ◽  
Vol 541-542 ◽  
pp. 622-627
Author(s):  
A.A. Kapse ◽  
P.R. Dongarwar ◽  
R.R. Gawande
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Cold Water ◽  
Hot Water ◽  
Full Length ◽  
Tube Heat Exchanger ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
Plain Tube

In the present work, the effects of insertion of helical screw tape on heat transfer characteristics and pressure drop in a concentric double tube heat exchanger are experimentally investigated. The heat exchanger has the outer (steel) and inner (copper) tube diameters of 50 mm and 25 mm respectively. The helical screw tape of diameter 19 mm is inserted into the inner tube to increase turbulence which helped to increase the heat transfer rate. The hot water was flowed through the inner tube and cold water was flowed in annulus. The helical screw tape was inserted in 1/3rd length and full length of the tube. The experiments are based on Reynolds number at tube inlet, ranging from 10000 to 42855. The experimental results show that the average Nusselt numbers and friction factors are respectively, 1.41 and 2.08 times over the plain tube for 1/3rd length insert and 1.87 and 4.31 times over the plain tube for full length insert. Furthermore, the enhancement ratio of the helical screw tape varies between 1.03 and 1.17, 1.02 and 1.26 for 1/3rd length insert and full length insert, respectively.

scholarly journals Design, Fabrication and Performance Evaluation of a Shell and Tube Heat Exchanger for Practical Application

2020 ◽  
Vol 5 (8) ◽  
pp. 835-845
Author(s):  
Bashiru Abdulmumuni ◽  
Adedeji Mathew Ayoade ◽  
Ologunye Opeyemi Buhari ◽  
Azeez Rasheed Olatunde ◽  
Fanifosi Johnson Olaniyi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Cold Water ◽  
Hot Water ◽  
Feed Water ◽  
Capacity Ratio ◽  
Overall Heat Transfer Coefficient ◽  
Fouling Factor

A heat exchanger is a device used to transfer thermal energy between two or more fluids, at different temperatures in thermal contact. This paper focuses on a shell-and-tubes heat exchanger that involves two fluids (hot water and cold water) in contact with each other while the cold water flows through the tubes and hot water through the shell. Heat exchangers have special and practical applications in the feed water cooler in the process industries, power plants, chemical plants, refineries, process applications as well as refrigeration and air conditioning industry. The design calculations were carried out to determine the specifications of essential parameters for the development of the heat exchanger, data generated from the theoretical formulae were used to fabricate the heat exchanger using some locally available and durable materials, and the performance of the system was evaluated. Some of the parameters evaluated include heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor. The heat exchanger was tested under various flow conditions and the results obtained were as follows; cold water inlet temperatures of (26, 26, 26, 27and 27) ºC increased to (59, 44, 39, 47 and 35) ºC after (10, 7½, 6½  8,  and 6) minutes and the hot water temperatures decreased from (100, 80, 75, 87 and 73) ºC to (73, 59, 55, 62 and 50) ºC, respectively. The design data and test data were compared in terms of the heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor, the deviation is found to be 22.87%, 13.99%, 8.98%, 43.30%, and 43.30% respectively. The results obtained proved that the heat exchanger was effective, reliable and provides a good technical approach to evaluate the thermal performance of the heat exchanger and useful in conducting heat and mass transfer practical in thermodynamics laboratory.

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.

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