scholarly journals First Solution of Fractional Bioconvection with Power Law Kernel for a Vertical Surface

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1366
Author(s):  
Muhammad Imran Asjad ◽  
Saif Ur Rehman ◽  
Ali Ahmadian ◽  
Soheil Salahshour ◽  
Mehdi Salimi
Keyword(s):  
Heat Transfer ◽  
Vertical Surface ◽  
Heat Transfer Analysis ◽  
Physical Parameters ◽  
Governing Equations ◽  
Fluid Properties ◽  
The Impact ◽  
The Given ◽  
Graphical Illustration ◽  
Fractional Parameter

The present study provides the heat transfer analysis of a viscous fluid in the presence of bioconvection with a Caputo fractional derivative. The unsteady governing equations are solved by Laplace after using a dimensional analysis approach subject to the given constraints on the boundary. The impact of physical parameters can be seen through a graphical illustration. It is observed that the maximum decline in bioconvection and velocity can be attained for smaller values of the fractional parameter. The fractional approach can be very helpful in controlling the boundary layers of the fluid properties for different values of time. Additionally, it is observed that the model obtained with generalized constitutive laws predicts better memory than the model obtained with artificial replacement. Further, these results are compared with the existing literature to verify the validity of the present results.

Heat Transfer Analysis of Jet Impingement Cooling on a Simulated Ceramic Matrix Composite Surface

2017 ◽  
Author(s):  
Karthik Krishna ◽  
Mark Ricklick
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Matrix Composite ◽  
Ceramic Matrix Composite ◽  
Jet Impingement ◽  
Ceramic Matrix ◽  
Heat Transfer Analysis ◽  
Test Surface ◽  
Composite Surface ◽  
The Impact

Ceramic Matrix Composite is a woven material characterized by a significant level of surface waviness of 35–60μm and surface roughness of 5–6μm. To be implemented in a future gas turbine engine they will be cooled traditionally to increase power and efficiency. To analyze the CMC surface effects on heat transfer rate, an impinging circular jet on a simulated CMC surface is studied experimentally and the CMC surface is represented by a high resolution CNC machined surface. The test parameters are jet to plate distance of 7 jet diameters, oblique impingement angles of 45° and 90° and Reynolds numbers of 11,000 to 35,000. The test surface is broken down into constant temperature segments, and individual segment Nusselt number is determined and plotted for the various impingement cases studied. Area-Averaged results show negligible changes in average Nusselt number as compared to the hydrodynamically smooth surface. The impact of the CMC surface feature is negligible compared to the uncertainty in heat transfer coefficient, and therefore traditional design tools can be utilized.

Design Studies for a Solar Reactor Based on a Simple Radiative Heat Exchange Model

2005 ◽  
Vol 127 (3) ◽  
pp. 425-429 ◽  
Author(s):  
C. Wieckert
Keyword(s):  
Heat Transfer ◽  
Solar Power ◽  
Radiation Heat Transfer ◽  
Heat Transfer Analysis ◽  
Physical Parameters ◽  
Concentrated Solar Power ◽  
Radiation Heat ◽  
Small Aperture ◽  
Lower Cavity ◽  
Solar Reactor

A high-temperature solar chemical reactor for the processing of solids is scaled up from a laboratory scale (5kW concentrated solar power input) to a pilot scale (200kW). The chosen design features two cavities in series: An upper cavity has a small aperture to let in concentrated solar power coming from the top. It serves as the solar receiver, radiant absorber, and radiant emitter to a lower cavity. The lower cavity is a well-insulated enclosure. It is subjected to thermal radiation from the upper cavity and serves in our application as the reaction chamber for a mixture of ZnO and carbon. Important insight for the definition of the geometrical parameters of the pilot reactor has been generated by a radiation heat transfer analysis based on the radiosity enclosure theory. The steady-state model accounts for radiation heat transfer within the solar reactor including reradiation losses through the reactor aperture, wall losses due to thermal conduction and heat consumption by the endothermic chemical reaction. Key results include temperatures of the different reactor walls and the thermal efficiency of the reactor as a function of the major geometrical and physical parameters. The model, hence, allows for a fast estimate of the influence of these parameters on the reactor performance.

scholarly journals Formations of Silicon Carbide and Epoxy Matrix Radiator: An Experimental Design, Dimension and Formulations

2019 ◽  
Vol 9 (1) ◽  
pp. 1793-1796
Keyword(s):  
Heat Transfer ◽  
Silicon Carbide ◽  
Experimental Design ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Research Work ◽  
Heat Transfer Analysis ◽  
The Given ◽  
Design Dimension

The greatest dealon the article have to approach the experimental design, dimensions and formulations in Silicon Carbide and Epoxy Matrix Radiator. The experiment prepared as per the fabrication chart behind that known about the characterization of material and proposal layout of fabrication work. Among the research work, concentrated the formation of silicon carbide epoxy matrix radiator in the given configuration and composition prepared as a high thermal conductive Epoxy resin is mixed at the ratio of 20wt% of epoxy resin 80% of Silicon Carbide. As silicon carbide has higher thermal conductivity and lowerthermal expansion than Aluminium and then the experimented result determined by the rate of heat transfer analysis such as the mode of heat transfer like Conduction, Convection and Radiation of the materials (Aluminium 6061 and Sic + Epoxy Resin). The following heat transfer characteristics formulated and calculated as per the given design, dimension and configuration of the materials.

Conjugate Heat Transfer Analysis on Generic Rim Seal Configurations in Rotor-Stator System

2018 ◽  
Author(s):  
Xingyun Jia ◽  
Liguo Wang ◽  
Qun Zheng ◽  
Hai Zhang ◽  
Yuting Jiang
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Minimum Mass ◽  
Aerodynamic Efficiency ◽  
Axial Clearance ◽  
The Impact

Performance of generic rim seal configurations, axial-clearance rim seal (ACS), radial-clearance rim seal (RCS), radial-axial clearance rim seal (RACS) are compared under realistic working conditions. Conjugate heat transfer analysis on rim seal is performed in this paper to understand the impact of ingestion on disc temperature. Results show that seal effectiveness and cooling effectiveness of RACS are the best when compared with ACS and RCS, the minimum mass flow rate for seal of RACS is 75% of that of RCS, and 34.6% of ACS. Authors compare the disc temperature distribution between different generic rim seal configurations where the RACS seems to be favorable in terms of low disc temperature. In addition, RACS has higher air-cooled aerodynamic efficiency, minimizing the mainstream performance penalty when compared with ACS and RCS. Corresponding to the respective minimum mass flow rate for seal, the air-cooled aerodynamic efficiency of RACS is 23.71% higher than that of ACS, and 12.79% higher than the RCS.

Overall Effectiveness of a Blade Endwall With Jet Impingement and Film Cooling

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Amy Mensch ◽  
Karen A. Thole
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Jet Impingement ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Convective Cooling ◽  
Impingement Cooling ◽  
Internal Impingement ◽  
The Impact ◽  
Overall Effectiveness

Ever-increasing thermal loads on gas turbine components require improved cooling schemes to extend component life. Engine designers often rely on multiple thermal protection techniques, including internal cooling and external film cooling. A conjugate heat transfer model for the endwall of a seven-blade cascade was developed to examine the impact of both convective cooling and solid conduction through the endwall. Appropriate parameters were scaled to ensure engine-relevant temperatures were reported. External film cooling and internal jet impingement cooling were tested separately and together for their combined effects. Experiments with only film cooling showed high effectiveness around film-cooling holes due to convective cooling within the holes. Internal impingement cooling provided more uniform effectiveness than film cooling, and impingement effectiveness improved markedly with increasing blowing ratio. Combining internal impingement and external film cooling produced overall effectiveness values as high as 0.4. A simplified, one-dimensional heat transfer analysis was used to develop a prediction of the combined overall effectiveness using results from impingement only and film cooling only cases. The analysis resulted in relatively good predictions, which served to reinforce the consistency of the experimental data.

Effect of Porous Medium in Stagnation Point Flow of Ferrofluid Due to a Variable Convected Thicked Sheet

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Maria Imtiaz ◽  
Hira Nazar ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Differential Equations ◽  
Stagnation Point ◽  
Skin Friction Coefficient ◽  
Stagnation Point Flow ◽  
Heat Transfer Analysis ◽  
Series Solutions ◽  
The Impact

Abstract The focus of this paper is to study the effects of stagnation point flow and porous medium on ferrofluid flow over a variable thicked sheet. Heat transfer analysis is discussed by including thermal radiation. Suitable transformations are applied to convert partial differential equations to ordinary differential equations. Convergent results for series solutions are calculated. The impact of numerous parameters on velocity and temperature is displayed for series solutions. Graphical behavior for skin friction coefficient and Nusselt number is also analyzed. Numerical values of Nusselt number are tabulated depending upon various parameters

scholarly journals Fractional Boundary Layer Flow and Heat Transfer Over a Stretching Sheet With Variable Thickness

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Lin Liu ◽  
Liancun Zheng ◽  
Yanping Chen ◽  
Fawang Liu
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Stretching Sheet ◽  
Magnetic Parameter ◽  
Governing Equations ◽  
Velocity Boundary Layer ◽  
Flow And Heat Transfer ◽  
Temperature Boundary ◽  
Layer Flow ◽  
Fractional Parameter

The paper gives a comprehensive study on the space fractional boundary layer flow and heat transfer over a stretching sheet with variable thickness, and the variable magnetic field is applied. Novel governing equations with left and right Riemann–Liouville fractional derivatives subject to irregular region are formulated. By introducing new variables, the boundary conditions change as the traditional ones. Solutions of the governing equations are obtained numerically where the shifted Grünwald formulae are applied. Good agreement is obtained between the numerical solutions and exact solutions which are constructed by introducing new source items. Dynamic characteristics with the effects of involved parameters on the velocity and temperature distributions are shown and discussed by graphical illustrations. Results show that the velocity boundary layer is thicker for a larger fractional parameter or a smaller magnetic parameter, while the temperature boundary layer is thicker for a larger fractional parameter, a smaller exponent parameter, or a larger magnetic parameter. Moreover, it is thicker at a smaller y and thinner at a larger y for the velocity boundary layer with a larger exponent parameter while for the velocity and temperature boundary layers with a smaller weight coefficient.

Effects of Various Physical and Numerical Parameters on Heat Transfer in Vertical Passages at Relatively Low Heat Loading

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Amir Keshmiri
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Reynolds Numbers ◽  
Boussinesq Approximation ◽  
Low Flow ◽  
Physical Parameters ◽  
Pipe Length ◽  
Viscosity Models ◽  
Heat Loading ◽  
Fluid Properties

The present work is concerned with the modeling of buoyancy-modified mixed convection flows, such flows being representative of low-flow-rate flows in the cores of Gas-cooled Reactors. Three different eddy viscosity models (EVMs) are examined using the in-house code, “CONVERT.” All fluid properties are assumed to be constant, and buoyancy is accounted for within the Boussinesq approximation. Comparison is made against experimental measurements and the direct numerical simulations (DNS). The effects of three physical parameters including the heat loading, Reynolds number, and pipe length on heat transfer have been examined. It is found that by increasing the heat loading, three thermal-hydraulic regimes of “early onset of mixed convection,” “laminarization,” and “recovery” were present. At different Reynolds numbers, the three thermal-hydraulic regimes are also evident. The k-ε model of Launder and Sharma was found to be in the closest agreement with consistently normalized DNS results for the ratio of mixed-to-forced convection Nusselt number (Nu/Nu0). It was also shown that for the “laminarization” case, the pipe length should be at least “500× diameter” in order to reach a fully developed solution. In addition, the effects of two numerical parameters namely buoyancy production and Yap length-scale correction terms have also been investigated and their effects were found to be negligible on heat transfer and friction coefficient in ascending flows.

A Numerical Study of Three-Dimensional Convective Heat Transfer From a Window Covered by a Simple Partially-Open Plane Blind

2008 ◽  
Author(s):  
Patrick H. Oosthuizen ◽  
Murat Basarir ◽  
David Naylor
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Side Surface ◽  
Governing Equations ◽  
Three Dimensional Flow ◽  
Buoyancy Forces ◽  
Fluid Properties ◽  
Higher Temperature ◽  
Open Plane

Heat transfer from the room-side surface of a window covered by a plane blind to the surrounding room has been considered. The window is at a higher temperature than the air in the room. There is an open gap between the blind system and the window at the top of the window and the effect of the size of this gap on the window-to-air heat transfer rate has been numerically examined. Three-dimensional flow has been considered. The flow has been assumed to be steady and laminar and it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated by using the Boussinesq approach. It has also been assumed that the flow is symmetrical about the vertical centre-plane of the window. The solution has been obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in terms of dimensionless variables. Results have only been obtained for a Prandtl number of 0.7. The effects of the other dimensionless parameters on the window Nusselt number have been numerically determined.

Heat Transfer Analysis of a Finned Solar Air Heater

1988 ◽  
Vol 110 (2) ◽  
pp. 145-155 ◽  
Author(s):  
F. Issacci ◽  
Y. Zvirin ◽  
G. Grossman
Keyword(s):  
Heat Transfer ◽  
Theoretical Method ◽  
Lower Surface ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Solar Air Heater ◽  
Governing Equations ◽  
Reversed Flow ◽  
Air Heater ◽  
Transfer Processes

A theoretical method is presented for the investigation of a reflective fin solar air heater. The heat transfer processes include radiation in both the solar and IR spectra, mixed convection (forced and natural) in the air and conduction in the fins. The governing equations have been solved numerically to obtain the velocity and temperature fields in the developing and developed flow regions. The efficiency of the finned structure is then calculated, and the results of a parametric study are shown. It has been found that natural convection effects are significant and strong buoyancy leads to separation and reversed flow. The efficiency increases with lower surface emissivity and lower thermal conductivity of the fins.

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