The impact of air flow to the distribution of heat transfer coefficient on circular cylinder

2015 ◽  
Author(s):  
Pavel Beran
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Circular Cylinder ◽  
Transfer Coefficient ◽  
Air Flow ◽  
The Impact

Nanoparticle aggregation kinematics on the quadratic convective magnetohydrodynamic flow of nanomaterial past an inclined flat plate with sensitivity analysis

2021 ◽  
pp. 095440892110562
Author(s):  
AS Sabu ◽  
Joby Mackolil ◽  
B Mahanthesh ◽  
Alphonsa Mathew
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Sensitivity Analysis ◽  
Heat Transfer Coefficient ◽  
Heat Source ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
Inclined Plate ◽  
The Impact ◽  
The Heat Transfer Coefficient

The study focuses on the aggregation kinematics in the quadratic convective magneto-hydrodynamics of ethylene glycol-titania ([Formula: see text]) nanofluid flowing through an inclined flat plate. The modified Krieger-Dougherty and Maxwell-Bruggeman models are used for the effective viscosity and thermal conductivity to account for the aggregation aspect. The effects of an exponential space-dependent heat source and thermal radiation are incorporated. The impact of pertinent parameters on the heat transfer coefficient is explored by using the Response Surface Methodology and Sensitivity Analysis. The effects of several parameters on the skin friction and heat transfer coefficient at the plate are displayed via surface graphs. The velocity and thermal profiles are compared for two physical scenarios: flow over a vertical plate and flow over an inclined plate. The nonlinear problem is solved using the Runge–Kutta-based shooting technique. It was found that the velocity profile significantly decreased as the inclination of the plate increased on the other hand the temperature profile improved. The heat transfer coefficient decreased due to the increase in the Hartmann number. The exponential heat source has a decreasing effect on the heat flux and the angle of inclination is more sensitive to the heat transfer coefficient than other variables. Further, when radiation is incremented, the sensitivity of the heat flux toward the inclination angle augments at the rate 0.5094% and the sensitivity toward the exponential heat source augments at the rate 0.0925%. In addition, 41.1388% decrement in wall shear stress is observed when the plate inclination is incremented from [Formula: see text] to [Formula: see text].

scholarly journals 3D Numerical Simulation of Laminar Flow and Conjugate Heat Transfer through Fabric

2017 ◽  
Vol 17 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Guocheng Zhu ◽  
Dana Kremenakova ◽  
Yan Wang ◽  
Jiri Militky ◽  
Rajesh Mishra ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Laminar Flow ◽  
Transfer Coefficient ◽  
Heat Loss ◽  
Human Skin ◽  
Human Body ◽  
Conjugate Heat Transfer ◽  
Air Flow ◽  
The Heat Transfer Coefficient

AbstractThe air flow and conjugate heat transfer through the fabric was investigated numerically. The objective of this paper is to study the thermal insulation of fabrics under heat convection or the heat loss of human body under different conditions (fabric structure and contact conditions between the human skin and the fabric). The numerical simulations were performed in laminar flow regime at constant skin temperature (310 K) and constant air flow temperature (273 K) at a speed of 5 m/s. Some important parameters such as heat flux through the fabrics, heat transfer coefficient, and Nusselt number were evaluated. The results showed that the heat loss from human body (the heat transfer coefficient) was smallest or the thermal insulation of fabric was highest when the fabric had no pores and no contact with the human skin, the heat loss from human body (the heat transfer coefficient) was highest when the fabric had pores and the air flow penetrated through the fabric.

The Study of Heat Transfer Coefficient during Cooling Plates of High Strength

2015 ◽  
Vol 220-221 ◽  
pp. 760-764
Author(s):  
Marcin Janik ◽  
Tomasz Garstka ◽  
Aneta Krzyżańska ◽  
Marcin Knapiński ◽  
Anna Kawałek
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
High Strength ◽  
Accelerated Cooling ◽  
Plastic Properties ◽  
Cooling Intensity ◽  
Hot Rolled ◽  
The Impact ◽  
Selection Of

Nowadays methods of hot-rolled sheets should ensure high mechanical and plastic properties of sheets, in-line rolling. Such technologies require application of devices for accelerated cooling of a band after last deformation. The essential thing in this process is selection of an appropriate positioning of the cooling intensity. The paper presents results of the cooling intensity for the selected air-water nozzle. On the basis of the results, the map of distribution of heat transfer coefficient for the nozzle to the surface of the cooling was performed. These tests were carried out for different settings of water and air. The research was carried out for high-strength steel. The obtained results allow executing of computer simulation of the impact of cooling intensity on the final product’s structure.

Experiment Study of Heat Transfer in Aeroengine Bearing Chambers

2011 ◽  
Vol 86 ◽  
pp. 448-453
Author(s):  
Xi Chuan Yuan ◽  
Hui Guo ◽  
Liang Yun Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Transfer Coefficient ◽  
Transfer Test ◽  
Air Flow ◽  
Experiment Study ◽  
Work Condition ◽  
Oil Flow ◽  
Turboshaft Engine

In this paper, a method of heat transfer test research in aeroengine bearing chamber has been introduced. The method attains the law of heat transfer in bearing chamber and the influence of heat transfer coefficient on bearing dn value, oil flow, supply oil temperature, sealing air flow by simulating the oil work condition in turboshaft engine typical high temperature bearing chamber.

scholarly journals Performance of an internet data center refrigeration system using an evaporative cooler

2020 ◽  
Vol 194 ◽  
pp. 01027
Author(s):  
Shibo Zhao ◽  
Yonghui Zhang ◽  
Yunqi Nie ◽  
Pengyu Qu ◽  
Wenqiang Sun
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Data Center ◽  
Air Flow ◽  
Water Volume ◽  
Evaporative Cooler ◽  
Internet Data Center

The traditional refrigeration method of internet data center (IDC) is mostly air refrigeration, which has undesired cooling effect and high power consumption. This study addresses this problem and proposes an evaporative air cooler (EAC) suitable for IDC. Given the high specific heat capacity of water, the evaporative condensing coil and spray device are added to the evaporative cooler to enhance the heat transfer effect. Heat and mass transfer mathematical models are established to analyze the heat transfer performance. The mathematical model is used to simulate the profile of the heat and mass transfer coefficient of the EAC with the amount of spray water and air flow. The results show that when the air flow changes from 10 to 20 kg/s, the air equivalent heat transfer coefficient increases by about 41%. When the air flow rate is 20 kg/s and the spray water volume is 0.00124 kg/(mꞏs), the total heat transfer coefficient is increased by about 308% compared with the case without spray water.

scholarly journals Heat transfer in the vortex zone of a cyclone-bed chamber of furnace unit with fluidized bed

2019 ◽  
Vol 64 (1) ◽  
pp. 87-97
Author(s):  
E. A. Pitsuha ◽  
E. K. Buchilko ◽  
Yu. S. Teplitskii ◽  
D. S. Slizhuk
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Radial Direction ◽  
Air Flow ◽  
Air Flow Rate ◽  
Outlet Hole ◽  
The Heat Transfer Coefficient

An experimental investigation of the heat-transfer coefficient to a spherical probe in a cyclone-bed chamber with fluidized bed in the “cold” and “hot” regimes has been carried out. The heat-transfer coefficient was determined by the regular thermal regime. The dependences of the heat-transfer coefficient in the vortex-bed furnace on the various parameters: the diameter of the outlet hole, the air flow rate, the share of the bottom blast and the location of the probe were determined. It is revealed that in the “cold” regime the heat-transfer coefficient has practically constant value in the radial direction, it almost does not depend on the diameter of the outlet hole and the share of the bottom blast and depends significantly on the position of the probe along the height of the furnace and the air flow rate. The effect of flow swirling on the heat-transfer coefficient in a cyclone-bed chamber with fluidized bed is determined. When the fuel burns (“hot” regime), the heat-transfer coefficient is not constant in the radial direction and accept the maximum values in the central area of the chamber. At the same time, the part of conductive-convective component in the total heat-transfer coefficient to the spherical probe, depending on its radial position, is estimated at 40–70 %. The results can be used in the design and creation of modern high-efficiency furnaces for burning local solid biofuels.

scholarly journals Enhanced Solar Air Heaters For Crop Drying

2021 ◽  
pp. 1-5
Author(s):  
Kamlesh Sahu ◽  
◽  
Gyaneshwar Sanodiya ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Roughness Element ◽  
Air Flow ◽  
Thermal Capacity ◽  
Solar Air Heater ◽  
Artificial Roughness ◽  
Transfer Coefficients ◽  
Absorber Plate

Solar air heaters are placed on farms to provide heat for the drying of grain and crop harvesting and harvesting. The results of the thermal study showed that solar air heaters are capable of providing a sufficient increase in air temperature under the majority of crop drying circumstances studied. The restricted thermal capacity of air, as well as the low heat transfer coefficient between the absorber plate and the air flow via the ducting system, both contribute to the overall thermal efficiency of solar air heaters. Solar air heaters must be more efficient in order to be more affordable. This may be accomplished by increasing the heat transfer coefficient between the absorber plate and the air flow passing through the duct. More heat transfer coefficients can be increased by using either active or passive approaches. In most situations, it may be cost-effective to use solar air heaters and incorporate artificial roughness on the absorber plate. The rate of heat transmission from the solar air heater’s duct to the fluid flow may be increased by creating artificial roughness on the surface of the duct. The study focused on several roughness element geometries for solar air heater ducts, and the results indicated that there is a link between the two. This paper attempts to find ways to artificially increase the heat transfer capacity of solar air heaters’ ducts by using element geometries which have been utilised in solar air heaters’ heat transfer devices.

scholarly journals Numerical study of heat transfer in 90° bend tube by AI2O3 nano fluids using fluid injection

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hadi Mahdizadeh ◽  
Nor Mariah Adam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Volume Fraction ◽  
Fluid Injection ◽  
Content Type ◽  
Nano Fluid ◽  
The Impact

Purpose This paper aims to investigate increasing heat transfer in bend tube 90° by fluid injection using nano fluid flow that was performed by expending varying Reynolds number. This paper studies the increased heat transfer in the bent tube that used some parameters to examine the effects of volume fraction, nanoparticle diameter, fluid injection, Reynolds number on heat transfer and flow in a bend pipe. Design/methodology/approach Designing curved tubes increases the thermal conductivity amount between fluid and wall. It is used the finite volume method and simple algorithms to solve the conservation equations of mass, momentum and energy. The results showed that the nanoparticles used in bent tube transfusion increase the heat transfer performance by increasing the volume fraction; it has a direct impact on enhancing the heat transfer coefficient. Findings Heat transfer coefficient enhanced 1.5% when volume fraction increased from 2 % to 6%, the. It is due to the impact of nanoparticles on the thermal conductivity of the fluid. The fluid is injected into the boundary layer flow due to jamming that enhances heat transfer. Curved lines used create a centrifugal force due to the bending and lack of development that increase the heat transfer. Originality/value This study has investigated the effect of injection of water into a 90° bend before and after the bend. Specific objectives are to analyze effect of injection on heat transfer of bend tube and pressure drop, evaluate best performance of mixing injection and bend in different positions and analyze effect of nano fluid volume fraction on injection.

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