Effect of novel flow divider type turbulators on fluid flow and heat transfer

Nalavade, Sandeep P.; Prabhune, Chandrakant L.; Sane, N. K.

doi:10.1016/j.tsep.2018.12.004

Cited by 42 publications

(15 citation statements)

References 32 publications

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“…9.8% for Nu and 11.6 for f and shows in good agreement. Figure 12 shows the comparison of ratio Nu/Nus obtained from the proposed vortex generator (COVG) with some earlier smooth tube inserts found in the literature such as, wing vortex generator of Deshmukh, et al [8], perforated vortex generator of Chamoli et al [18], turbulator of Nalavade, et al [21]. The overall trend for various types of inserts shows that the decreasing in Re the value of Nu/Nus increases.…”

Section: Influence Of Angle Of Attackmentioning

confidence: 85%

Numerical and Experimental Investigations on Performance Evaluation of a Conical Offset Vortex Generator Inserts to Improve Convective Heat Transfer Coefficient

Mundhe

Bindu

2020

Journal of Thermal Engineering

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The passive augmentation technique is widely used by researchers from thermal engineering field and it has shown excellent results for convective heat transfer rate. This paper shows the numerical and experimental findings for convective heat transfer characteristics and friction coefficient. Tests were conducted for turbulent flow, using air as medium through a uniformly heated steel pipe containing a novel kind of insert named as Conical offset Vortex Generator (COVG). The simulation tests were performed for turbulent flow with varying Reynolds number in the range 4000 to 50000. The parameters were analyzed during tests are pitch to smooth tube diameter ratio (p/d) and angle of attack (α). Various simulation tests were carried out with the help of ANSYS Fluent software to optimize the geometry. The simulation tests were carried out for different angle of attack (α = 15°, 30°, 60°). COVG with angle of attack (α = 60°) shows more enhancement in heat transfer rate, hence it was used for the experimentation purpose. The experimentation is conducted for various pitch to diameter (p/d = 1.18, 1.97, 3.94). The numerical and experimental results show improvement in heat transfer rate as there is decrease in pitch to smooth tube diameter ratio (p/d) and it also increases the value of friction factor. The reason behind the improvement in heat transfer rate is that, the braking of thermal boundary layer near the wall surface. Experimental results show the enhancement of Nusselt number from 3.46-6.7.

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Section: Influence Of Angle Of Attackmentioning

confidence: 85%

Numerical and Experimental Investigations on Performance Evaluation of a Conical Offset Vortex Generator Inserts to Improve Convective Heat Transfer Coefficient

Mundhe

Bindu

2020

Journal of Thermal Engineering

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“…This correlation is a reliable interpolation of approximate analytical solutions of momentum and energy equations for pipe flows at constant heat flux, if constant properties are assumed. Since predicting experimental results with an accuracy of 5-10%, this model is regularly used as a basis for comparisons that do not involve experimental data [28,29].…”

Section: Correlations For Further Comparisonmentioning

confidence: 99%

“…correlations, those of Skupinski et al, Seban & Shimazaki, Gnielinski, Camaraza-Medina et al, Nalavade et al and Sandall et al (see Figure5). The selected models are the widely-acknowledged correlations in the technical literature[26][27][28][29][30][31][32].…”

mentioning

confidence: 99%

Application of the ‘Nusselt-Equation Simulated Evolution Method’ in Forced Convective Heat Transfer Modeling

Sánchez-Escalona¹,

Camaraza-Medina²,

Retirado-Mediaceja³

et al. 2021

IJDNE

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Reliability of heat exchangers thermal analysis strongly depends on the equations selected to determine local convective heat transfer coefficients. Chosen analogy among momentum, heat and mass transfer also plays a remarkable role. Within this context, the aim of the study was to validate a novel approach to obtain mean forced convective film coefficients under single-phase non-laminar fluid flow conditions, inside tubes. It relied on a comprehensive Nusselt-number equation that is able to evolve into different functional forms according to Reynolds-Colburn, Prandtl and von Karman analogies. Parameters estimation was carried out through Genetic Algorithms. Applied experimental database was numerically obtained by Taler by solving the energy conservation equation for fully developed turbulent flow in tubes with constant wall heat flux. Application of the method provided a new correlation, valid for 0.1 ≤ ≤ 10 3 and 3 × 10 3 ≤ ≤ 10 6 . Besides attaining a better fit to the experimental data as compared to benchmark expressions, it correlated very well with the results of reference models (Skupinski, Seban & Shimazaki, Gnielinski, Camaraza-Medina, Petukhov, and Sandall). The first assessment provided mean and maximum relative errors of 2.41% and 19.45%, respectively, while the second comparison resulted in deviations over the Nusselt number up to 20% in 92.59% of the data points. The implemented solution overcomes the drawbacks of non-linear and symbolic regression methods by allowing evolution of the regression function within a controlled mathematical environment. Future model improvements should investigate different fitting-intervals along with higher turbulence regions.

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“…A triple wing VG by Gautam [9] was tested under a circular tube showcasing a maximum improvement of 1.63 in the overall performance. Some of the other VG designs which influenced the heat transfer rate and flow friction are winglet VG by Islam [10,11], punched DWVG by Lei [12], Wijayanta [13], Skullong [14], double-sided DWT by Wijayanta [15,16] and flow divider type turbulators by Sandeep [17] are some of the recent augmented techniques. A Stepped conical Nozzle turbulators was designed by Orhan [18] saw an overall optimization of 11% compare to plain tube.…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation of Thermo-Hydraulic Performance Index of a Double Pipe Heat Exchanger Using Double Sided Louvered Winglet Tape

Thejaraju

Girisha²,

Manjunath³

et al. 2020

Journal of Thermal Engineering

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The decade has witnessed great importance of numerical techniques for scientists and researchers in deciding the correctness, stability, and reliability of new designs. In the present study a numerical technique has been implemented to investigate the thermo-hydraulic performance of the Louvered winglet tape inside the tube section of the double pipe heat exchanger. The Louvered winglet tape has been examined with the slope angle of 50, 100, 150 and 210 to study their thermal characteristics. The Reynolds number 4000-30000 was examined on slope angle of 50, 100, 150 and 210 to study their flow characteristics in the turbulent domain. A smooth pipe was examined to evaluate heat transfer characteristics in terms of Nusselt number and friction coefficient over augmented tube with Louvered winglet tape. The results show a satisfactory performance of Louvered winglet tape over the smooth tube with a similar trend of friction factor, Nusselt number, and thermo-hydraulic performance index (THPI). The percentage of increment of the Nusselt number of the results is found to be 237.04%, 258.4%, 275.11%, and 289.72% when compared to smooth pipe with respect to slope angle of 50, 100, 150 and 210, respectively. The amount of increase in the friction factor in comparison with plain tube is 5.13, 6.73, 8.33, and 11.73 times of that of smooth pipe with respect to slope angle of 50, 100, 150 and 210, respectively. The Louvered winglet tape with slope angle 150 has shown to be promising with respect to higher THPI when considering with other slope angle of 50, 100, and 210. The maximum THPI of 1.85 was obtained for slope angle 150 at Re 12000. Similarly, the THPI values for other slope angle 50, 100, and 210 are 1.71, 1.78 and 1.69. In addition to better performance the Louvered winglet tape can be easily fabricated and adapted for a wide variety of heat transfer industries.

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Effect of novel flow divider type turbulators on fluid flow and heat transfer

Cited by 42 publications

References 32 publications

Numerical and Experimental Investigations on Performance Evaluation of a Conical Offset Vortex Generator Inserts to Improve Convective Heat Transfer Coefficient

Numerical and Experimental Investigations on Performance Evaluation of a Conical Offset Vortex Generator Inserts to Improve Convective Heat Transfer Coefficient

Application of the ‘Nusselt-Equation Simulated Evolution Method’ in Forced Convective Heat Transfer Modeling

Numerical Evaluation of Thermo-Hydraulic Performance Index of a Double Pipe Heat Exchanger Using Double Sided Louvered Winglet Tape

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