scholarly journals EXPERIMENTAL STUDY ON IN-POND HEAT EXCHANGER PROVIDED WITH TWISTED TAPES

2017 ◽  
Vol 10 (13) ◽  
pp. 467
Author(s):  
Karunamurthy K ◽  
Nayan Singh ◽  
Vivek Singh
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Saline Water ◽  
Salinity Gradient ◽  
Swirl Flow ◽  
Laboratory Model ◽  
Solar Ponds ◽  
Twisted Tapes ◽  
Twist Ratio

In-pond heat exchangers (IHE) are used in salinity gradient solar ponds (SGSP), to transfer heat from hot saline water of the lower convective zone to the heat transfer medium. The performance of the SGSP depends on the performance of the IHE, which in turn depends on the method of heat transfer augmentation. A laboratory model IHE was fabricated to augment the heat transfer using helical twisted tapes (HTTs). The effects of varying twist ratio and double TTs on pressure drop and heat transfer were studied in this experimental work. Conventional HTTs of three twist ratios (Y=7, 9, 11), twin TTs of co-swirl flow (CoTT), and counter-swirl TTs (CTT) with Y=7 were provided in the flow path of the heat exchanger tube for analysis. From the results, it is observed that TTs with less twist ratio yielded higher rate of heat transfer by sacrificing the pressure drop. Compared to single TT, double TT provided better thermal performance. The pressure drop and rate of heat transfer for CTT are more compared to all other cases, including double TT with co-swirl flow.

Pressure Drop During Forced Convection Boiling of R-12 Under Swirl Flow

1982 ◽  
Vol 104 (4) ◽  
pp. 758-762 ◽  
Author(s):  
K. N. Agrawal ◽  
H. K. Varma ◽  
S. Lal
Keyword(s):  
Pressure Drop ◽  
Forced Convection ◽  
Flow Boiling ◽  
Horizontal Tube ◽  
Swirl Flow ◽  
Flow Data ◽  
Nelson Model ◽  
Twisted Tapes ◽  
Twist Ratio ◽  
Flow Pressure

This investigation deals with the pressure drop during forced convection boiling of R-12 under swirl flow inside a horizontal tube. Plain flow and swirl flow pressure drop data are reported for an electrically heated, horizontal, stainless steel, round test-section fitted with twisted tapes having twist ratios from 3.76 to 10.15. A correlation has been presented expressing the swirl flow boiling pressure drop in terms of the twist ratio and the plain flow boiling pressure drop calculated by the Martinelli-Nelson model. The proposed correlation predicts the swirl flow data to within ± 20 percent of the observed values.

Experimental Analysis on Heat Transfer Enhancement of Double Pipe Heat Exchanger Using Alumina/Water Nanofluid and Baffled Twisted Tape Inserts

2015 ◽  
Vol 752-753 ◽  
pp. 458-465
Author(s):  
P.C. Sreekumar ◽  
K. Krishnamoorthy ◽  
R. Ratheesh
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Twisted Tape ◽  
Twisted Tapes ◽  
Twist Ratio ◽  
Double Pipe ◽  
Pipe Heat

Heat transfer augmentation techniques ultimately results in the reduction of thermal resistance in a conventional heat exchanger by generating higher convective heat transfer coefficient. Present study with the use of Alumina (Al2O3)/water nanofluid and baffled twisted tape inserts in double pipe heat exchanger as compound augmentation technique. Experiments were conducted to evaluate the heat transfer coefficient and friction factor for the flow through the inner tube of heat exchanger in turbulent flow range (8000<Re<60000). The effect of rectangular, circular, triangular baffled twisted tape having twist ratio (y/w) 4.2 and twisted tapes without baffles of twist ratio (y/w) 4.2 and 5.2 were studied. Experiments were conducted for both water and 0.1% volume concentration Alumina/water nanofluid. It is found that the enhancement of heat transfer coefficient by using rectangular baffled twisted tape and nanofluid is about 20%. Performance evaluation criteria were found for water and nanofluid and it was observed that rectangular baffled twisted tape performs better than other twisted tapes.

scholarly journals Thermo-Hydraulic Performance Analysis on the Effects of Truncated Twisted Tape Inserts in a Tube Heat Exchanger

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1652
Author(s):  
Mehdi Ghalambaz ◽  
Ramin Mashayekhi ◽  
Hossein Arasteh ◽  
Hafiz Muhammad Ali ◽  
Pouyan Talebizadehsardari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Twisted Tapes ◽  
Plain Tube

This paper investigates the convective heat transfer in a heat exchanger equipped with twisted tape elements to examine effects of the twisted tape truncation percentage, pitch value, position and Reynolds number using 3D numerical simulation. A symmetric heat flux is applied around the tube as the studied heat exchanger. Based on the influences in both heat transfer enhancement and pressure drop, the performance evaluation criterion (PEC) is utilized. Inserting twisted tape elements and reducing the pitch value significantly augment the Nusselt number, friction coefficient and PEC number compared to the plain tube. For the best case with a Reynolds number of 1000, the average Nusselt number increases by almost 151%, which is the case of fully fitted twisted tape at a pitch value of L/4. Moreover, increasing the twisted tape truncation percentage reduces both heat transfer and pressure drop. Furthermore, the highest heat transfer rate is achieved when the truncated twisted tape is located at the entrance of the tube. Finally, it is concluded that for P = L, L/2, L/3 and L/4, the optimum cases from the viewpoint of energy conservation are twisted tapes with truncation percentages of 75, 50, 50 and 0%, in which the related PEC numbers at a Reynolds number of 1000 are almost equal to 1.08, 1.24, 1.4 and 1.76, respectively.

The Influence of Twisted Tapes in Subcritical, Once-Through Vapor Generators in Counter flow

1974 ◽  
Vol 96 (3) ◽  
pp. 365-370 ◽  
Author(s):  
M. Cumo ◽  
G. E. Farello ◽  
G. Ferrari ◽  
G. Palazzi
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Exchanger ◽  
Joule Heating ◽  
Swirl Flow ◽  
Twisted Tape ◽  
Counter Flow ◽  
Tubular Heat Exchanger ◽  
Annular Gap ◽  
Twisted Tapes

The swirl flow of Freon 12 in a tubular heat exchanger, indirectly heated by forced convection of water in an annular gap, is studied. Two identical situations are compared, with and without a twisted tape, to deduce the influence of the swirl flow in the particularly interesting boundary condition of indirect heating by another fluid (and not simply of uniform Joule heating). The heat transfer is greatly increased by the swirl flow, up to a factor of two at the burnout or dryout point.

Thermal Performance in Circular Tube with Co/Counter-Twisted Tapes

2014 ◽  
Vol 931-932 ◽  
pp. 1198-1202 ◽  
Author(s):  
Suriya Chokphoemphun ◽  
Chayodom Hinthao ◽  
Smith Eiamsa-ard ◽  
Pongjet Promvonge ◽  
Chinaruk Thianpong
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Circular Tube ◽  
Experimental Results ◽  
Enhanced Heat Transfer ◽  
Twisted Tapes ◽  
Twist Ratio

Thiswork presents an experimental study on enhanced heat transfer and pressure loss characteristics in a tube having a uniform heat-fluxed wall by using small double and triple co-and counter-twisted tapes at two twist ratios, y/w=4 and 4.5. The investigation has been conducted for Reynolds number from 5300-20,000. The experimental results of the heat transfer and pressure drop are proposed in terms of Nusselt number and friction factor, respectively.The experimental results reveal thatthe maximum TEF for the triple counter-twisted tapesat smaller twist ratio isabout 1.26.

Sign in / Sign up

Export Citation Format

Share Document