Thermal-Hydraulic Performance Analysis by Means of Rectangular Winglet Vortex Generators in a Channel: An Experimental Study

2021 ◽  
Vol 6 (3) ◽  
pp. 150-153
Author(s):  
Oktarina Heriyani ◽  
Mohamad Djaeni ◽  
. Syaiful
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Performance Evaluation ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Rectangular Channel ◽  
Evaluation Criteria ◽  
Hydraulic Performance ◽  
Vortex Generators ◽  
Fluid Flow Velocity

Vortex generators (VGs) are one of the effective passive models used to increase the heat transfer rate in heat exchangers. In this experiment, heat transfer from six cylinders heated to the airflow was improved by attaching rectangular winglet vortex generators (RWVGs) to a plate in a rectangular channel. The installation aimed to increase the value of the thermal-hydraulic performance evaluation criteria in the line. This experimental study was carried out by varying the fluid flow velocity from 0.4 m/s to 2 m/s with an interval of 0.2 m/s in the channel. Three pairs of VGs were arranged in both in-line and staggered configurations. The experimental results show that the thermal-hydraulic performance evaluation criteria for three pairs of vortex generators in the staggered configuration was 15.17% higher than the baseline, while the thermal-hydraulic performance of the in-line arrangement was 1.54% higher than the staggered one.

scholarly journals Assessment of economic, thermal and hydraulic performances a corrugated helical heat exchanger filled with non-Newtonian nanofluid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ibrahim ◽  
Ebrahem A. Algehyne ◽  
Tareq Saeed ◽  
Abdallah S. Berrouk ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Economic Analysis ◽  
Evaluation Criteria ◽  
Methyl Cellulose ◽  
Hydraulic Performance ◽  
Two Phase ◽  
Heat Transfer Efficiency ◽  
Helical Heat Exchanger

AbstractImproved heat transfer efficiency with considering economic analysis in heating systems is an interesting topic for researchers and scientists in recent years. This research investigates the heat transfer rate (HTR) and flow of non-Newtonian water-Carboxyl methyl cellulose (CMC) based Al2O3 nanofluid in a helical heat exchanger equipped with common and novel turbulators using two-phase model. The requirements for dimensions and cost reduction and also energy saving in thermal systems are the main goal of this study. According to gained results usage of corrugated channel in helical heat exchanger has a considerable influence on thermal and hydraulic performance evaluation criteria (THPEC) index of helical heat exchanger and can improve the THPEC index. Thus, Re = 5000 is obtained as an optimum value, in which the maximum THPEC value is achieved. As it is found in this paper, in case of using novel heat exchanger instead of the basic smooth system, the thermal properties (by considering Nusselt number) increases about 210%, the hydraulic performance (friction factor) reduces about 28%, performance evaluation criteria index increases about 57% and the material consumption (in case of similar THPEC) decreases about 31%. In another word, with considering economic analysis for the basic and novel system which has same efficiencies, the novel one has lower length and consequently 31% lower material.

scholarly journals Performance evaluation of tube-in-tube heat exchangers with heat transfer enhancement in the annulus

2006 ◽  
Vol 10 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Ventsislav Zimparov ◽  
Plamen Penchev ◽  
Joshua Meyer
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Evaluation Criteria ◽  
Relative Reduction ◽  
Geometrical Parameters ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Finned Tubes

Different techniques as angled spiraling tape inserts, a round tube in side a twisted square tube and spiraled tube in side the annulus have been used to enhance heat transfer in the annulus of tube-in-tube heat exchangers. The heat transfer enhancement in the shell can be supplemented by heat transfer augmentation in tubes using twisted tape inserts or micro-finned tubes. The effect of the thermal resistance of the condensing refrigerant could also be taken into consideration. To assess the benefit of using these techniques extended performance evaluation criteria have been implemented at different constraints. The decrease of the entropy generation can be combined with the relative in crease of the heat transfer rate or the relative reduction of the heat transfer area to find out the geometrical parameters of the tubes for optimal thermodynamics performance. The results show that in most of the cases considered, the angled spiraling tube insert technique is the most efficient.

scholarly journals HEAT TRANSFER ENHANCEMENT AND PRESSURE DROP FOR FIN-AND-TUBE COMPACT HEAT EXCHANGERS WITH DELTA WINGLET-TYPE VORTEX GENERATORS

2018 ◽  
Vol 16 (2) ◽  
pp. 233 ◽  
Author(s):  
Seyed Alireza Ghazanfari ◽  
Malan Abdul Wahid
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Pressure Loss ◽  
Transfer Rate ◽  
Vortex Generators ◽  
Compact Heat Exchanger ◽  
Compact Heat Exchangers ◽  
Delta Winglet

Heat transfer rate, pressure loss and efficiency are considered as the most important parameters in designing compact heat exchangers. Despite different types of heat exchangers, fin-and-tube compact heat exchangers are still common device in different industries due to the diversity of usage and the low space installation need. The efficiency of the compact heat exchanger can be increased by introducing the fins and increasing the heat transfer rate between the surface and the surroundings. Numerous modifications can be applied to the fin surface to increase heat transfer. Delta-winglet vortex generators (VGs) are known to enhance the heat transfer between the energy carrying fluid and the heat transfer surfaces in plate-fin-and-tube banks, but they have drawbacks as well. They increase the pressure loss and this should be considered. In this paper, the thermal efficiency of compact heat exchanger with VGs is investigated in different variations. The angle of attack, the length and horizontal and vertical position of winglet are the main parameters to consider. Numerical analyses are carried out to examine finned tube heat exchanger with winglets at the fin surface in a relatively low Reynolds number flow for the inline tube arrangements. The results showed that the length of the winglet significantly affects the improvement of heat transfer performance of the fin-and-tube compact heat exchangers with a moderate pressure loss penalty. In addition, the results show that the optimization cannot be performed for one criterion only. More parameters should be considered at the same time to run the process properly and improve the heat exchanger efficiency.

A Study About Performance Evaluation Criteria of Tube Banks With Various Shapes and Arrangements Using Numerical Simulation

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Amin Jodaei ◽  
Kamiar Zamzamian
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Evaluation Criteria ◽  
Cross Flow ◽  
Transfer Coefficients ◽  
Tube Bank ◽  
Shaped Tube ◽  
Tube Banks

Tube bank heat exchangers are designed to efficiently transfer heat between two fluids. Shapes and arrangements of tubes in heat exchangers have significant effects in heat transfer and pressure drop of fluid. In this study, the three-dimensional (3D) numerical investigation is performed to determine heat transfer coefficients, friction factor, and performance evaluation criteria (PEC) of cam-shaped tube banks in aerodynamic and inverse aerodynamic directions in the cross flow air and compared with those of elliptical tube banks in heat exchanger. The arrangements of tubes are aligned and staggered with longitudinal pitch of 44.88 mm and transverse pitch of 28.05 mm. Reynolds number in the range of 11,500–18,500 was used, and the tube surface temperature was fixed and considered 352 K. Results indicate the superior heat transfer of elliptical tube bank over the cam-shaped tube banks in inverse aerodynamic and aerodynamic directions in both arrangements. Moreover, the PEC of the cam-shaped tube banks with inverse aerodynamic and aerodynamic directions and elliptical tube bank in aligned arrangement are approximately 1.4, 1.1, and 1.6, respectively. The obtained results for staggered arrangements are also 1.5, 1.3, and 1.8, respectively.

scholarly journals Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

2021 ◽  
Vol 39 (3) ◽  
pp. 797-809
Author(s):  
Syaiful ◽  
Bambang Yunianto ◽  
Carisya Dara Salsabila ◽  
Berkah Fajar T.K. ◽  
Maria F. Soetanto
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Convective Heat Transfer Coefficient ◽  
Attack Angle ◽  
Vortex Generators ◽  
Longitudinal Vortex

In fin and tube heat exchangers, the gas passing through the fin has a lower thermal conductivity than the fluid passing through the tube. The low thermal conductivity brings a high thermal resistance, which suppresses the heat transfer rate. A common practice to enhance fin-side heat transfer is to generate longitudinal vortex by mounting vortex generators (VGs) on the fin. This paper aims to investigate how longitudinal vortex generator (LVG) improves heat transfer and pressure drop. Numerical simulations were carried out to analyze three types of VGs. The installation of VGs was varied with the attack angle changing from 10°, 15°, to 20° with a 1-3-4-7 VG arrangement on the tube. The flow velocity was expressed in Reynolds number (Re) between 364 and 689. The enhancement of heat transfer rate and improvement of pressure drop were analyzed between three types of VG, three different attack angles, and four types of winglet installation, compared to baseline. The simulation results show that the highest convective heat transfer coefficient (84.85%) was achieved by the VG composed of seven concave delta winglet pairs (CDWPs) at the attack angle of 20° and Re = 689; CDWP VG provides the highest heat transfer improvement among all cases.

scholarly journals Efek vortex generators terhadap peningkatan perpindahan panas pada aliran melewati heated tubes

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Yafid Effendi ◽  
Ali Rosyidin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Friction Factor ◽  
Rectangular Channel ◽  
Evaluation Criteria ◽  
Vortex Generators ◽  
High Thermal Resistance ◽  
Flow Pressure ◽  
Delta Winglet

In this decade, improving the rate of heat transfer has become a big challenge. The high thermal resistance of the gas side of the heat exchanger has an impact on the low rate of heat transfer. Therefore, an experimental study was carried out aimed at looking at conditions of hot temperature and decreased air flow pressure through a heated tube in a rectangular channel using artificial surfaces, namely the concave delta winglet and delta winglet vortex generators. Concave delta winglet vortex generators (CDW VGs) are installed in-line and staggered with one, and two pairs are arranged in common-flow-down (CFD) in the direction of flow with an angle of attack of 15o. The experimental results show that the best thermal performance is observed in the use of two rows CDW VGs staggered, where the value of performance evaluation criteria (PEC) is 28.88% higher than the use of CDW VGs in-line, DW VGs staggered and DW VGs in-line at the same Reynolds number. At the same Reynolds number, the Nusselt number ratio and the friction factor ratio increased 45.25% and 152.05% respectively, occurring in two rows of CDW VGs staggered compared to other vortex generators.Keywords: vortex generators, heat transfer, Nusselt number, friction factor, PEC

Comparative Performance of Rippled Fin Plate Fin and Tube Heat Exchangers

1989 ◽  
Vol 111 (1) ◽  
pp. 21-28 ◽  
Author(s):  
J. D. Maltson ◽  
D. Wilcock ◽  
C. J. Davenport
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Wind Tunnel ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Evaluation Criteria ◽  
Performance Characteristics ◽  
Published Data ◽  
Transfer Enhancement ◽  
Comparative Performance

Continuous rippled fins are preferred to interrupted fins in applications where fouling by fibrous matter or insects is a problem. The performance characteristics of three rippled fin heat exchangers have been measured in a thermal wind tunnel. The results of these measurements are reported and comparisons are made with published data on similar surfaces. The performance evaluation criteria used as the basis for the comparisons were those recommended by Shah (1978). The tested rippled fin surfaces were found to have a higher performance than a similar surface reported in Kays and London (1984). The heat transfer enhancement was found to be dependent upon the profile of the fin.

Sign in / Sign up

Export Citation Format

Share Document