Abstract:In the present study, the effect of a helical coiled tape on the heat transfer characteristics in a tubular heat exchanger has been studied. Numerical analysis is carried out in a tubular heat exchanger with a helical coiled tape insert under laminar flow conditions. The heat transfer characteristics, like Nusselt number (Nu) and friction factor (f), have been determined. Numerical modeling is undertaken and validated using analytical results. To study the parametric variation, simulation is carried out for di… Show more
“…If twisted tapes are utilized, the augmentation of heat transfer in the transitional flow regime is greater than that in the laminar or turbulent flow regimes, according to Meyer and Abolarin 19 and Abolarin et al 20 A tubular heat exchanger with a helically coiled tape insert was studied numerically in laminar flow circumstances by Kumar et al 6 Different width ratios (WRs) and TRs have been determined to investigate how they affect the heat transmission properties such as Nusselt number (Nu) and friction factor (f). The maximum thermohydraulic performance index was recorded for a combination of WR = 3 and TR = 1.25, according to the measured values.…”
Section: The Deltamentioning
confidence: 99%
“…Tubes with inserts have been used as one of the passive heat transfer enhancement techniques and are the most widely used tubes in several heat transfer applications; for example, heat recovery processes, air conditioning and refrigeration systems, and chemical reactors. 6 The insert increases the turbulence intensity which is the major influencing factor for heat transfer enhancement. In fact, using insert increases both desirable heat transfer rate and undesirable friction loss (pressure drop).…”
Section: Introductionmentioning
confidence: 99%
“…It was concluded that the installed tube inserts in the heat exchanger tube led to a significant increase in Nu number and energy saving. Chamoli et al 11 developed perforated vortex generators with three relative pitch lengths (2,4,6) and four distinct perforation indices (4%, 8%, 12%, and 16%) to enhance the convective heat transmission. The main results showed that the thermal enhancement factor increased as the perforation indexes increased, but the heat transfer and pressure drop increased as the perforation indexes decreased and the pitch lengths increased.…”
Experimental and computational investigations have studied the heat transfer, friction factor, and enhancement of heat transfer in a horizontal tube equipped with rectangular cut ring inserts and different diameter ratios (D/d) and pitch-to-tube diameter ratios (p/d t ). In the present study, air having a Reynolds no. range of 6700-20,100 was used as a working fluid. Three diameter ratios (D/d) were considered experimentally and numerically as 1.2, 1.25, and 1.3, and the pitch-totube diameter ratio (p/d t ) was (1, 0.625, and 0.5). Air was forced as working fluid through the tube and a uniform heat flux of 2000, 3500, and 5000 W/m 2 was applied through the tube's exterior surface. On the basis of the turbulence model k-ɛ with various parameters, three-dimensional numerical simulations using the ANSYS Fluent software 17.2 were investigated. Under the same working conditions, the results manifested a higher heat transfer rate and friction factor as compared to the plain tube. The results evinced that the Nusselt number for a horizontal tube equipped with rectangular cut ring inserts having various pitch ratios and diameter ratios is discovered to be higher than that for the plain tube. With the increased ring spacing, the overall improvement in heat transfer occurred. And, with a rise in Re, the total
“…If twisted tapes are utilized, the augmentation of heat transfer in the transitional flow regime is greater than that in the laminar or turbulent flow regimes, according to Meyer and Abolarin 19 and Abolarin et al 20 A tubular heat exchanger with a helically coiled tape insert was studied numerically in laminar flow circumstances by Kumar et al 6 Different width ratios (WRs) and TRs have been determined to investigate how they affect the heat transmission properties such as Nusselt number (Nu) and friction factor (f). The maximum thermohydraulic performance index was recorded for a combination of WR = 3 and TR = 1.25, according to the measured values.…”
Section: The Deltamentioning
confidence: 99%
“…Tubes with inserts have been used as one of the passive heat transfer enhancement techniques and are the most widely used tubes in several heat transfer applications; for example, heat recovery processes, air conditioning and refrigeration systems, and chemical reactors. 6 The insert increases the turbulence intensity which is the major influencing factor for heat transfer enhancement. In fact, using insert increases both desirable heat transfer rate and undesirable friction loss (pressure drop).…”
Section: Introductionmentioning
confidence: 99%
“…It was concluded that the installed tube inserts in the heat exchanger tube led to a significant increase in Nu number and energy saving. Chamoli et al 11 developed perforated vortex generators with three relative pitch lengths (2,4,6) and four distinct perforation indices (4%, 8%, 12%, and 16%) to enhance the convective heat transmission. The main results showed that the thermal enhancement factor increased as the perforation indexes increased, but the heat transfer and pressure drop increased as the perforation indexes decreased and the pitch lengths increased.…”
Experimental and computational investigations have studied the heat transfer, friction factor, and enhancement of heat transfer in a horizontal tube equipped with rectangular cut ring inserts and different diameter ratios (D/d) and pitch-to-tube diameter ratios (p/d t ). In the present study, air having a Reynolds no. range of 6700-20,100 was used as a working fluid. Three diameter ratios (D/d) were considered experimentally and numerically as 1.2, 1.25, and 1.3, and the pitch-totube diameter ratio (p/d t ) was (1, 0.625, and 0.5). Air was forced as working fluid through the tube and a uniform heat flux of 2000, 3500, and 5000 W/m 2 was applied through the tube's exterior surface. On the basis of the turbulence model k-ɛ with various parameters, three-dimensional numerical simulations using the ANSYS Fluent software 17.2 were investigated. Under the same working conditions, the results manifested a higher heat transfer rate and friction factor as compared to the plain tube. The results evinced that the Nusselt number for a horizontal tube equipped with rectangular cut ring inserts having various pitch ratios and diameter ratios is discovered to be higher than that for the plain tube. With the increased ring spacing, the overall improvement in heat transfer occurred. And, with a rise in Re, the total
“…Likewise, that lead to enhancing the value of convective thermal resistance then highly pressure drop increases and hence the heat performance improves. Afsharpanah et al, Al-Obaidi et al, and Kumar et al [28][29][30][31][32][33][34][35][36] studied using different types of twisted tape in heat exchanger pipes. The noted that using these dives can improved the overall heat performance in pipes.…”
In different energy conservation types, heat transfer improvement is a significant field that is directly connected to systems of economic efficiency. In this analysis, different twisted tape configurations are considered such as the augmentation thermal approach, the impact of various twisted tape parameters on the thermal performance of flow pattern, improvement of heat transfer are numerically conducted. The geometrical configurations used for this investigation include twisted tape thickness, twisted tape width, inward thickness and number of turns. The design of the technique of the experiment is used to investigate the effect of these parameters on hydraulic flow structure and enhancement of heat transfer. The Taguchi method is based on analysis of changes and performs the orthogonal arrays. Besides this, the orthogonal array of L16 is selected for this numerical work. The average percentage error between the experimental and computational fluid dynamics (CFD) outcomes for Nu number and friction factor are noted at about 6.5% and 4.5%. It is observed that the best twisted tape configuration design is obtained by applying CFD methodology compared with the Taguchi method to improve the heat performance using the performance evaluation factor (PEF) was more than 1.2. The maximum value of temperature differences and friction factor was for model 13. Moreover, the thermal performance was good as the values of PEF and the values of PEF are greater than 1.
An experimental analysis has been carried out to investigate the thermal and friction factor characteristics of fluid flow in a tube with double strip helical screw tape (DS-HST) inserts with different values of twist ratio and compared with single strip helical screw tape inserts and plain tube. Water is used as a working fluid at different flow rates with constant heat flux conditions. CFD analysis is also carried out to visualize thermal and fluid flow characteristics of fluid flow in tube with inserts. Experimental results have showed that Nusselt number and friction factor have attained excellent enhancement with double strip helical screw tape inserts in the range of flow rates than single strip helical screw tape inserts at the value of twist ratio 1.5. Correlation is also developed for Nusselt number with a range of Reynolds number, twist ratio and number of strips. Moreover, the performance ratio has attained maximum value at twist ratio of 2.5 with high values of flow rate. It is concluded that DS-HST is able to attain enhancement in the efficiency of heat exchanger, causing a reduction in size for thermal applications.
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