scholarly journals Heat transfer augmentation in water-based TiO_2 nanoparticles through a converging/diverging channel by considering Darcy-Forchheimer porosity

2019 ◽  
Vol 65 (4 Jul-Aug) ◽  
pp. 373 ◽  
Author(s):  
K. Ganesh Kumar ◽  
S.A. Shehzad ◽  
T. Ambreen ◽  
And M.I. Anwar
Keyword(s):  
Heat Transfer ◽  
Flow Parameter ◽  
Surface Drag ◽  
Transfer Rates ◽  
Heat Transfer Augmentation ◽  
Temperature Distributions ◽  
Diverging Channel ◽  
Divergent Channel ◽  
The Impact ◽  
Parameter Influence

This article executes MHD heat transport augmentation in aqueous based  nanoparticles fluid flow over convergent/divergent channel. Joule heating, magnetic field and Darcy-Forchheimer effects are explained for concentration and temperature distributions. Darcy-Forchheimer theory is utilized to explore the impact of porous medium. The system of partial differential expressions is transformed into ordinary ones and evaluated numerically by implementing RKF-45 scheme. Expressions for velocity and temperature profile are derived and plotted under the assumption of flow parameter. Influence of various parameters on heat transfer rates and surface drag force are discussed with the help of table and plots.

Transverse magnetic flow over a Reiner–Philippoff nanofluid by considering solar radiation

2019 ◽  
Vol 33 (36) ◽  
pp. 1950449 ◽  
Author(s):  
M. Gnaneswara Reddy ◽  
Sudha Rani ◽  
K. Ganesh Kumar ◽  
Asiful H. Seikh ◽  
Mohammad Rahimi-Gorji ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Transverse Magnetic ◽  
Surface Drag ◽  
Transfer Rates ◽  
Heat Transfer Augmentation ◽  
Flow And Heat Transfer ◽  
Plastic Fluid ◽  
Dilatant Fluid ◽  
The Impact ◽  
Linear Radiation

This paper reports the flow and heat transfer augmentation on Reiner–Philippoff nanofluid over stretching sheet. The effect of transverse magnetic field and thermal radiation are explored for temperature distributions. Transformations are used to reduce system of partial differential equations into ordinary ones and are solved numerically by using RKF-45 Method. Expressions for velocity and temperature profile are derived and plotted under the assumption of flow parameter. Influence of various parameters on surface drag force and heat transfer rates have been discussed with the help of tables and plots. It is noticed that the impact of pseudo plastic fluid, Newtonian fluid and dilatant fluid are highly contrasted in higher Ha. Furthermore, production of heat transfer is more in nonlinear radiation when compared to linear radiation.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

scholarly journals Cumulative Impact of Micropolar Fluid and Porosity on MHD Channel Flow: A Numerical Study

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Kottakkaran Sooppy Nisar ◽  
Aftab Ahmed Faridi ◽  
Sohail Ahmad ◽  
Nargis Khan ◽  
Kashif Ali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Chemical Reaction ◽  
Micropolar Fluid ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
X Rays ◽  
Cumulative Impact ◽  
Transfer Rates ◽  
Mass And Heat Transfer ◽  
The Impact

The mass and heat transfer magnetohydrodynamic (MHD) flows have a substantial use in heat exchangers, electromagnetic casting, X-rays, the cooling of nuclear reactors, mass transportation, magnetic drug treatment, energy systems, fiber coating, etc. The present work numerically explores the mass and heat transportation flow of MHD micropolar fluid with the consideration of a chemical reaction. The flow is taken between the walls of a permeable channel. The quasi-linearization technique is utilized to solve the complex dynamical coupled and nonlinear differential equations. The consequences of the preeminent parameters are portrayed via graphs and tables. A tabular and graphical comparison evidently reveals a correlation of our results with the existing ones. A strong deceleration is found in the concentration due to the effect of a chemical reaction. Furthermore, the impact of the magnetic field force is to devaluate the mass and heat transfer rates not only at the lower but at the upper channel walls, likewise.

Heat Transfer Enhancement in Annular Shear-Thinning Flows Over a Sudden Pipe Expansion

2017 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Power Law ◽  
Shear Thinning ◽  
Diameter Ratio ◽  
Transfer Enhancement ◽  
Heat Transfer Augmentation ◽  
Prandtl Numbers ◽  
Power Law Index ◽  
The Impact

Heat transfer enhancement in suddenly expanding annular pipe flows of a shear-thinning non-Newtonian fluid is studied within the steady laminar flow regime. Conservation of mass, momentum, and energy equations, along with the power-law constitutive model are numerically solved. The impact of inflow inertia, annular-nozzle-diameter-ratio, k, power-law index, n, and Prandtl numbers, is reported for: Re = {50, 100}, k = {0, 0.5, 0.7}; n = {1, 0.8, 0.6}; and Pr = {1, 10, 100}. Heat transfer enhancement downstream of the expansion plane, i.e., Nusselt numbers, Nu, higher than the fully developed value, in the downstream pipe, is observed only for Pr = 10 and 100. Higher Prandtl numbers, power-law index values, and annular diameter ratios, in general, reflect a more dramatic heat transfer augmentation downstream of the expansion plane. Heat transfer augmentation for Pr = 10 and 100, is more dramatic for suddenly expanding annular flows, in comparison with suddenly expanding pipe flow. For a given annular diameter ratio and Reynolds numbers, increasing the Prandtl number from Pr = 10 to Pr = 100, always results in higher peak Nu values, for both Newtonian and shear-thinning non-Newtonian flows.

scholarly journals Effect of Conical Strip Inserts and ZrO2/DI-Water Nanofluid on Heat Transfer Augmentation: An Experimental Study

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4554
Author(s):  
Mohamed Iqbal Shajahan ◽  
Jee Joe Michael ◽  
M. Arulprakasajothi ◽  
Sivan Suresh ◽  
Emad Abouel Nasr ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Test Section ◽  
Volume Concentration ◽  
Swirl Flow ◽  
Performance Ratio ◽  
Transfer Rates ◽  
Heat Transfer Augmentation ◽  
Twist Ratio ◽  
Constant Wall Heat Flux

There is a significant enhancement of the heat transfer rate with the usage of nanofluid. This article describes a study of the combination of using nanofluid with inserts, which has proved itself in attaining higher benefits in a heat exchanger, such as the radiator in automobiles, industries, etc. Nanofluids are emerging as alternative fluids for heat transfer applications due to enhanced thermal properties. In this paper, the thermal hydraulic performance of ZrO2, awater-based nanofluid with various volume concentrations of 0.1%, 0.25%, and 0.5%, and staggered conical strip inserts with three different twist ratios of 2.5, 3.5, and 4.5 in forward and backward flow patterns were experimentally tested under a fully developed laminar flow regime of 0–50 lphthrough a horizontal test pipe section with a length of 1 m with a constant wall heat flux of 280 W as the input boundary condition. The temperatures at equidistant position and across the test section were measured using K-type thermocouples. The pressure drop across the test section was measured using a U-tube manometer. The observed results showed that the use of staggered conical strip inserts improved the heat transfer rates up to that of 130.5%, 102.7%, and 64.52% in the forward arrangement, and similarly 145.03%, 116.57%, and 80.92% in the backward arrangement with the twist ratios of 2.5, 3.5, and 4.5 at the 0.5% volume concentration of ZrO2 nanofluid. It was also seen that the improvement in heat transfer was comparatively lower for the other two volume concentrations considered in this study. The twist ratio generates more swirl flow, disrupting the thermal hydraulic boundary layer. Nanofluids with a higher volume concentration lead to higher heat transfer due to higher effective thermal conductivity of the prepared nanofluid. The thermal performance factor (TPF) with conical strip inserts at all volume concentrations of nanofluids was perceived as greater than 1. A sizable thermal performance ratio of 1.62 was obtained for the backward-arranged conical strip insert with 2.5 as the twist ratio and a volume concentration of 0.5% ZrO2/deionized water nanofluid. Correlations were developed for the Nusselt number and friction factor based on the obtained experimental data with the help of regression analysis.

Flow Inertia and Heat Transfer in Suddenly Expanding Annular Shear-Thinning Flows

2017 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Shear Thinning ◽  
Heat Transfer Augmentation ◽  
Flow And Heat Transfer ◽  
Prandtl Numbers ◽  
Power Law Index ◽  
Annular Pipe ◽  
Flow Inertia ◽  
The Impact

The impact of flow inertia on flow and heat transfer in suddenly expanding annular pipe flows of a shear-thinning non-Newtonian fluid is studied within the steady laminar flow regime. The equations governing conservation of mass, momentum, and energy, along with the power-law constitutive model are numerically solved using a finite-difference numerical scheme. The influence of inflow inertia, annular-nozzle-diameter-ratio, k, power-law index, n, and Prandtl numbers, is reported for: Re = {50, 100}, k = {0, 0.5}; n = {1, 0.6}; and Pr = {1, 10, 100}. Heat transfer augmentation, downstream the plane of expansion, is only observed for Pr = 10 and 100. The extent and intensity of recirculation in the corner region, increases with inflow inertia. Higher Reynolds and Prandtl numbers, power-law index values, and annular diameter ratios, in general, reflect a more dramatic heat transfer augmentation downstream of the expansion plane.

Heat Transfer Augmentation From Extended Surface Using Dimples

2018 ◽  
Author(s):  
Jay D. Mehta ◽  
Fay N. Colah ◽  
Anurag P. Rao ◽  
Vineeta P. Pendse ◽  
Vyankatesh U. Bagal ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Transfer Rate ◽  
Surface Modifications ◽  
Exposed Surface ◽  
Transfer Rates ◽  
Heat Transfer Augmentation ◽  
Extended Surface ◽  
Extended Surfaces ◽  
Exposed Surface Area

This paper concentrates on comparing dimples to improve the heat transfer rate from extended surfaces under forced convection conditions. Dimples are milled on the surface of the fins while keeping the exposed surface area between the various designs as constant. Spherical dimples, ellipsoidal dimples, cylindrical dimples, and pyramidal dimples are selected as part of the paper. Experimental results are compared with results obtained from simulation. The paper concludes that surface modifications improve the heat transfer rates. The paper also compares the thermal performance of various shapes of dimples.

Impact of Uncertainty On Prediction of Supercritical CO2 Properties and Nusselt Numbers

2021 ◽  
Author(s):  
Neil Sullivan ◽  
Yang Chao ◽  
Sandra Boetcher ◽  
Mark Ricklick
Keyword(s):  
Heat Transfer ◽  
Critical Point ◽  
Supercritical Co2 ◽  
Transfer Rates ◽  
Nusselt Numbers ◽  
Property Data ◽  
Highly Sensitive ◽  
Fluid Properties ◽  
Temperature And Pressure ◽  
The Impact

Abstract The impact of measurement uncertainty on heat transfer coefficient correlations for supercritical CO2 is investigated. Selection of appropriate temperature- and pressure-dependent reference quantities for these correlations, such as thermal conductivity, appears to have a large effect on predicting heat transfer rates. Supercritical CO2 work heavily depends on tabular real fluid property data, which show that fluid properties have very large gradients with respect to temperature and pressure near the critical point. The sharp gradients imply heat transfer predictions are highly sensitive to the accuracy of temperature and pressure experimental measurements in this region. Root sum of squares (RSS) uncertainties of various property values indicate predictably large (on the order of 1000%) uncertainties in calculated Reynolds, Prandtl, and Nusselt numbers near the critical point. Interestingly, uncertainties remain several times the calculated value for operating pressures (between 7.5 and 8.5 MPa) common in the experimental literature, highlighting a need for careful application of correlations near the pseudocritical line, and the benefits of presenting dimensional data in the literature.

Numerical Analysis of Flow Structure and Heat Transfer Characteristics in Dimpled Channels With Secondary Protrusions

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Yonghui Xie ◽  
Zhongyang Shen ◽  
Di Zhang ◽  
Phillip Ligrani
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Numerical Analysis ◽  
Thermal Performance ◽  
The Other ◽  
Combination Effect ◽  
Enhancement Ratio ◽  
Heat Transfer Characteristics ◽  
Transfer Rates ◽  
Heat Transfer Augmentation

Dimple structure is an effective heat transfer augmentation approach on coolant channel due to its advantage on pressure penalty. The implication of secondary protrusion, which indicates protrusion with smaller dimension than dimple, will intensify the Nusselt number Nu inside dimple cavity without obvious extra pressure penalty. The objective of this study is to numerically analyze the combination effect of dimples and secondary protrusion. Different protrusion–dimple configurations including protrusion print-diameter Dp, protrusion–dimple gap P, and staggered angle α are investigated. From the results, it is concluded that the implication of secondary protrusion will considerably increase the heat transfer rates inside dimple cavity. Cases 4 and 6 possess the highest Nusselt number enhancement ratio Nu/Nu0 reaching up to 2.1–2.2. The additional pressure penalty brought by the protrusion is within 15% resulting in total friction ratio f/f0 among the range of 1.9–2.1. Dimpled channels with secondary protrusions possess higher thermal performance factor TP, defined as (Nu/Nu0)/(f/f0)1/3, among which cases 4 and 6 are the optimal structures. Besides this, the TP of protrusion–dimple channels are comparable to the other typical heat transfer devices, and higher TP can be speculated after a more optimal dimple shape or combination with ribs and fins.

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