Comparative Thermal Performance Analysis on Helical Screw Insert in Tube With Number of Strips With Nanofluid at Laminar Flow Regime

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Shashank Ranjan Chaurasia ◽  
R. M. Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Flow Regime ◽  
Thermal Performance ◽  
Power Plants ◽  
Nanofluid Flow ◽  
Laminar Flow Regime ◽  
Twist Ratio ◽  
Single Strip

Abstract The experimental analysis is arranged to evaluate the thermal hydraulic performance on nanofluid flow in helical screw insert with tube at a number of strips and different twist ratios in laminar flow regime. The single strip (SS) helical screw inserts are also compared with the double strip (DS) helical screw inserts. The heat transfer enhancement is achieved with nanofluid flow in double strip as compared with single strip helical screw insert at decreased values of twist ratio and increased values of Reynolds number. A maximum enhancement of 421% is found in the value of Nusselt number with double strip helical screw insert at twist ratio of 1.5 and low value of Reynolds number in the flow of nanofluid than water in plain tube. The common correlations of Nusselt number and friction factor are generated. The thermal performance factor (TPF) is achieved at a maximum value of 2.42 with double strip than single strip helical screw inserts at twist ratio of 2.5 and low value of Reynolds number. The present analysis shows suitability of the double strip helical screw insert to enable miniaturization of the heat exchangers. A compact heat exchanger decreases the size of thermal application such as solar water heater, solar power plants, electronic cooling systems, radiator, etc., which could save environment by pollution reduction with utilization of energy.

Experimental and numerical thermal performance analysis with exergy destruction on nanofluid flow in tube with double strip helical screw inserts

2021 ◽  
pp. 095765092098214
Author(s):  
Shashank Ranjan Chaurasia ◽  
RM Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Thermal Performance ◽  
Power Plants ◽  
Exergy Destruction ◽  
Water Heater ◽  
Nanofluid Flow ◽  
Maximum Enhancement ◽  
Twist Ratio ◽  
Single Strip

Experimental and numerical analysis is arranged with exergy destruction to evaluate thermal performance of system on nanofluid flow in tube with single and double strip helical screw inserts at different values of twist ratio in laminar flow regime. CFD analysis has occurred on the fluent workbench of ANSYS software. The Nusselt number attained enhancement with the flow of nanofluid in double strip helical screw inserts as compared with single strip helical screw inserts at decreasing values of twist ratio and increasing values of Reynolds number. Maximum enhancement of 421% is found with Nusselt number in the flow of nanofluid in tube with double strip helical screw insert at 1.5 of twist ratio and lower value of Reynolds number as compared with the flow of water in plain tube. Common correlations of Nusselt number and friction factor are generated. Exergy destruction number is attained less than one value for both types of inserts at different values of twist ratio and Reynolds number, whereas attained lower value with the flow of nanofluid in tube with double strip helical screw insert at twist ratio of 1.5 and low value of Reynolds number. Heat transfer enhancement number is attained more than one value for both types of inserts with different values of twist ratio and Reynolds number, whereas double strip helical screw inserts attained maximum value at twist ratio of 1.5 in the range of Reynolds number. Therefore, double strip helical screw inserts are the best inserts as compared with single strip helical screw inserts to compact the size of heat exchangers, whereby size of many thermal applications could be compact such as solar water heater, electronic cooling devices, automobile radiator, power plants etc.

Heat transfer enhancement using second mode self-oscillating structures

2019 ◽  
Vol 30 (7) ◽  
pp. 3827-3842
Author(s):  
Samer Ali ◽  
Zein Alabidin Shami ◽  
Ali Badran ◽  
Charbel Habchi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Flow Regime ◽  
Vortex Generator ◽  
Reynolds Numbers ◽  
Content Type ◽  
Laminar Flow Regime ◽  
Second Mode

Purpose In this paper, self-sustained second mode oscillations of flexible vortex generator (FVG) are produced to enhance the heat transfer in two-dimensional laminar flow regime. The purpose of this study is to determine the critical Reynolds number at which FVG becomes more efficient than rigid vortex generators (RVGs). Design/methodology/approach Ten cases were studied with different Reynolds numbers varying from 200 to 2,000. The Nusselt number and friction coefficients of the FVG cases are compared to those of RVG and empty channel at the same Reynolds numbers. Findings For Reynolds numbers higher than 800, the FVG oscillates in the second mode causing a significant increase in the velocity gradients generating unsteady coherent flow structures. The highest performance was obtained at the maximum Reynolds number for which the global Nusselt number is improved by 35.3 and 41.4 per cent with respect to empty channel and rigid configuration, respectively. Moreover, the thermal enhancement factor corresponding to FVG is 72 per cent higher than that of RVG. Practical implications The results obtained here can help in the design of novel multifunctional heat exchangers/reactors by using flexible tabs and inserts instead of rigid ones. Originality/value The originality of this paper is the use of second mode oscillations of FVG to enhance heat transfer in laminar flow regime.

Thermal Performance With Entropy Generation Analysis of Fluid Flow in a Heat Exchanger Pipe With Single and Double Strip Helical Screw Tape Inserts

2020 ◽  
Author(s):  
Shashank Ranjan Chaurasia ◽  
R. M. Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Entropy Generation ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Maximum Enhancement ◽  
Twist Ratio ◽  
Single Strip

Abstract In heat exchangers, twisted tape insert is a technique to enhance heat transfer. In this paper, the experimental investigation is arranged to analyse thermal performance and entropy generation analysis on fluid flow in helical screw inserts with number of strips. The Nusselt number is achieved enhancement with double strip as compared to single strip helical screw inserts at decreased values of twist ratio and increased values of flow rates. The Nusselt number is achieved maximum enhancement of 112% with double strip helical screw insert than plain tube at 4000 of Reynolds number, whereas it is found higher value at Reynolds number of 16000. The common correlations of Nusselt number and friction factor with repect of Reynolds number, number of the strips and twist ratio are generated. The entropy generation analysis is also performed. The thermal performance factor is found increment with double strip than single strip helical screw inserts at twist ratio of 2.5 and 3, whereas, it is attained maximum value of 1.5 at twist ratio 2.5 and Reynolds number of 16000 with double strip helical screw insert. The double strip helical screw inserts are suitable for reducing the size of heat exchanger, which could dercrease the size of many thermal applications as solar water heater, radiator, electronic cooling systems.

Numerical and experimental thermal performance with entropy generation analysis on tube with helical screw tape inserts at number of strips in turbulent flow

2020 ◽  
pp. 095440622093773
Author(s):  
Shashank Ranjan Chaurasia ◽  
RM Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Entropy Generation ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Maximum Enhancement ◽  
Twist Ratio ◽  
Plain Tube ◽  
Volume Method ◽  
Single Strip

In the heat exchangers, twisted tape insert is a technique to enhance heat transfer. In this paper, the experimental and numerical investigations are arranged to analyze thermal performance with entropy generation analysis on single and double strip helical screw tape inserts. The finite volume method is used with shear stress transport K-ω model to analyze fluid flow in tube with inserts. The Nusselt number attained enhancement with double strip as compared to single strip helical screw inserts at decreased values of twist ratio and increased values of Reynolds number. However, the Nusselt number attained maximum enhancement of 112% with double strip helical screw insert than plain tube at 4000 of Reynolds number (Re). The common correlations for Nusselt number and friction factor are generated with respect to Reynolds number, number of the strips and twist ratio. Entropy generation analysis is also performed. The thermal performance factor attained its enhancement with double strip than single strip helical screw inserts at twist ratio of 2.5 and 3; whereas, double strip helical screw insert attained maximum value of 1.5 at twist ratio of 2.5 and Reynolds number of 16000. The double strip helical screw inserts are suitable for miniaturization of heat exchanger.

Transition Criteria for Laminar to Turbulent Flow for Yield Power Law (YPL) Fluids Based on Stability Analysis

2013 ◽  
Author(s):  
Goktug Kalayci ◽  
Evren M. Ozbayoglu ◽  
Stefan Z. Miska ◽  
Mengjiao Yu ◽  
Nicholas Takach ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Stability Analysis ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Friction Factor ◽  
Yield Stress ◽  
Flow Regime ◽  
Power Law ◽  
Laminar Flow Regime

It is well known that a Newtonian fluid with the presence of solid particles in suspension behaves non-Newtonian. Higher the solid content, more significant the yield stress of the fluid. Determination of the hydraulic behavior of fluids having a significant yield stress is a challenging task. For engineering purposes, pressure drop within the system, during pipeline transportation, has to be estimated carefully and accurately. Flow regime plays a vital role during hydraulic calculations. The inaccurate determination of flow regime can lead us to large errors in frictional pressure drop calculations and ultimately leads to error in designing and flow assurance point of view, since hydraulic calculations are including a friction factor term, which is a direct function of flow regime. In general, Reynolds number is the main parameter used by the industry for determining the flow regime, and the friction factor. This approach works reasonably accurate for Newtonian fluids. However, as the yield stress of the fluid increases, this conventional technique for determining the flow regime is not as accurate. Although many approaches have been introduced for estimating the flow regime for non-Newtonian fluids, there exists a lack of information and confidence of such predictions for fluids having high yield stress, such as Yield Power Law (YPL) fluids (i.e., Herchel-Bulkley). (1)τ=τy+Kγm This study presents an analytical solution for predicting the transition from laminar to non-laminar flow regime based on Ryan & Johnson’s approach using the stability analysis and equation of motion for YPL fluids. Comparing with the experimental results for YPL fluids under different flow conditions, including laminar and non-laminar flow regimes, show that presented approach gives a better estimation of the transition from laminar to non-laminar flow regime than conventional Reynolds number approach. In some cases, it is observed that although the Reynolds number is high, flow is still laminar, which is predicted accurately using the presented model. This study provides a higher accuracy in estimating the flow regime, which leads to a higher confidence in hydraulic designs and determining limitations of the system in concern.

Thermal-Hydraulic Performance Analysis of Fluid Flow in Tube With Helical Screw Inserts in Transition Flow

2020 ◽  
Author(s):  
Shashank Ranjan Chaurasia ◽  
R. M. Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Performance Analysis ◽  
Hydraulic Performance ◽  
Transition Flow ◽  
Maximum Enhancement ◽  
Transition Flow Regime ◽  
Twist Ratio ◽  
Single Strip

Abstract An experimental analysis is arranged to evaluate thermal hydraulic performance analysis on fluid flow in helical screw inserts in tube with number of strips and different twist ratios in Transition flow regime. Single strip insert is also compared with double strip inserts of helical screw inserts with three values of twist ratios. Heat transfer enhancement is achieved with fluid flow in double strip as compared to single strip helical screw insert at decreases values of twist ratios and increases values of Reynolds number (Re). Maximum enhancement in the value of Nusselt number is achieved with double strip inserts at low value of twist ratio and Reynolds number as compared to Single strip inserts. Common correlations of Nusselt number and friction factor are generated. Thermal performance factor (TPF) is achieved maximum values with double strip insert at all flow rates at 2.5 of twist ratio than single strip inserts. Double strip inserts show suitability of helical screw insert in heat exchangers to compact the size of thermal applications.

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