scholarly journals Numerical Investigation Of The Impingement Of A Planar Jet of Nanofluids On A V-Shaped Plate

2021 ◽  
Author(s):  
Nishma Bhatt
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Propylene Glycol ◽  
Base Fluid ◽  
Volume Fraction ◽  
Cooling System ◽  
Jet Impingement ◽  
Numerical Code ◽  
Jet Flows ◽  
Transfer Enhancement

An effective way to enhance the heat dissipation in industrial heat transfer devices is impinging of the fluid jet. Due to the higher dissipation heat flux, jet flows can be used for to control the temperature of high intensity heat sources. Traditional fluids such as water, ethylene and propylene glycol, and oils offer heat transfer capabilities that are adequate for many applications. There are several options to increase the effectiveness of the heat transfer characteristics for these fluids, for instance, using jet flows, and increasing the surface area of the heat transfer object. However, with the advances in nanotechnology and material science, nanofluids offer an attractive alternative option. Nanofluids refer to a dispersion of metallic or non-metallic particles with dimensions smaller than 100 nm in a base fluid like water, ethylene and propylene glycol, oil. Nanofluids have been shown to have an enhanced heat transfer characteristic, because of their high thermal conductivity. In this Project, Heat transfer enhancement of an impinging liquid jet on a V-shape target plate cooling system, has been investigated numerically, by replacing the base fluid, water, with Al2O3–water nanofluid. To conduct the research, literature review on nanofluid heat transfer enhancement, jet impingement, and nanofluids jet impingement, has been conducted. Numerical model has been built using ANSYS Workbench 16.0. After validating the numerical code with the previous experimental data, the effect of nanoparticles volume fraction, jet-surface distance and jet’s Reynolds number on the heat transfer enhancement has been investigated

scholarly journals Numerical Investigation Of The Impingement Of A Planar Jet of Nanofluids On A V-Shaped Plate

2021 ◽  
Author(s):  
Nishma Bhatt
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Propylene Glycol ◽  
Base Fluid ◽  
Volume Fraction ◽  
Cooling System ◽  
Jet Impingement ◽  
Numerical Code ◽  
Jet Flows ◽  
Transfer Enhancement

An effective way to enhance the heat dissipation in industrial heat transfer devices is impinging of the fluid jet. Due to the higher dissipation heat flux, jet flows can be used for to control the temperature of high intensity heat sources. Traditional fluids such as water, ethylene and propylene glycol, and oils offer heat transfer capabilities that are adequate for many applications. There are several options to increase the effectiveness of the heat transfer characteristics for these fluids, for instance, using jet flows, and increasing the surface area of the heat transfer object. However, with the advances in nanotechnology and material science, nanofluids offer an attractive alternative option. Nanofluids refer to a dispersion of metallic or non-metallic particles with dimensions smaller than 100 nm in a base fluid like water, ethylene and propylene glycol, oil. Nanofluids have been shown to have an enhanced heat transfer characteristic, because of their high thermal conductivity. In this Project, Heat transfer enhancement of an impinging liquid jet on a V-shape target plate cooling system, has been investigated numerically, by replacing the base fluid, water, with Al2O3–water nanofluid. To conduct the research, literature review on nanofluid heat transfer enhancement, jet impingement, and nanofluids jet impingement, has been conducted. Numerical model has been built using ANSYS Workbench 16.0. After validating the numerical code with the previous experimental data, the effect of nanoparticles volume fraction, jet-surface distance and jet’s Reynolds number on the heat transfer enhancement has been investigated

Study of the boundary layer heat transfer of nanofluids over a stretching sheet: Passive control of nanoparticles at the surface

2015 ◽  
Vol 93 (7) ◽  
pp. 725-733 ◽  
Author(s):  
M. Ghalambaz ◽  
E. Izadpanahi ◽  
A. Noghrehabadi ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Heat Transfer Enhancement ◽  
Base Fluid ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Enhancement Ratio ◽  
Transfer Enhancement

The boundary layer heat and mass transfer of nanofluids over an isothermal stretching sheet is analyzed using a drift-flux model. The relative slip velocity between the nanoparticles and the base fluid is taken into account. The nanoparticles’ volume fractions at the surface of the sheet are considered to be adjusted passively. The thermal conductivity and the dynamic viscosity of the nanofluid are considered as functions of the local volume fraction of the nanoparticles. A non-dimensional parameter, heat transfer enhancement ratio, is introduced, which shows the alteration of the thermal convective coefficient of the nanofluid compared to the base fluid. The governing partial differential equations are reduced into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using the fourth-order Runge–Kutta and Newton–Raphson methods along with the shooting technique. The effects of six non-dimensional parameters, namely, the Prandtl number of the base fluid Prbf, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, variable thermal conductivity parameter Nc and the variable viscosity parameter Nv, on the velocity, temperature, and concentration profiles as well as the reduced Nusselt number and the enhancement ratio are investigated. Finally, case studies for Al2O3 and Cu nanoparticles dispersed in water are performed. It is found that increases in the ambient values of the nanoparticles volume fraction cause decreases in both the dimensionless shear stress f″(0) and the reduced Nusselt number Nur. Furthermore, an augmentation of the ambient value of the volume fraction of nanoparticles results in an increase the heat transfer enhancement ratio hnf/hbf. Therefore, using nanoparticles produces heat transfer enhancement from the sheet.

scholarly journals Enhanced heat transfer characteristics of conjugated air jet impingement on a finned heat sink

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 279-288 ◽  
Author(s):  
Shuxia Qiu ◽  
Peng Xu ◽  
Liping Geng ◽  
Arun Mujumdar ◽  
Zhouting Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Flow Characteristics ◽  
Jet Impingement ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Air Jet

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.

Experimental Investigation of Submerged Impinging Jet Using Cu-Water Nanofluid

2010 ◽  
Author(s):  
Qiang Li ◽  
Yimin Xuan ◽  
Feng Yu ◽  
Junjie Tan
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Volume Fraction ◽  
Cooling System ◽  
Heated Surface ◽  
Particle Volume Fraction ◽  
Jet Impingement ◽  
Particle Volume ◽  
Impingement Cooling ◽  
System Pressure

An experimental investigation was performed to study the heat transfer and flow features of Cu-water nanofluids (Cu particles with 26 nm diameter) in a submerged jet impingement cooling system. Three particular nozzle-to-heated surface distances (2, 4 and 6 mm) and four particle volume fractions (1.5%, 2.0%, 2.5% and 3.0%) are involved in the experiment. The experimental results reveal that the suspended nanoparticles increase the heat transfer performance of the base liquid in the jet impingement cooling system. Within the range of experimental parameters considered, it has been found that highest surface heat transfer coefficients can be achieved using a nozzle-to-surface distance of 4 mm and the nanofluid with 3.0% particle volume fraction. In addition, the experiments show that the system pressure drop of the dilute nanofluids is almost equal to that of water under the same entrance velocity.

scholarly journals Heat Transfer Enhancement of Impingement Cooling by Adopting Circular-Ribs or Vortex Generators in the Wall Jet Region of A Round Impingement Jet

2020 ◽  
Vol 5 (3) ◽  
pp. 17 ◽  
Author(s):  
Ken-Ichiro Takeishi ◽  
Robert Krewinkel ◽  
Yutaka Oda ◽  
Yuichi Ichikawa
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Cooling System ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Vortex Generators ◽  
Wall Jet ◽  
Transfer Enhancement ◽  
Impingement Cooling ◽  
Impingement Jet

In the near future, when designing and using Double Wall Airfoils, which will be manufactured by 3D printers, the positional relationship between the impingement cooling nozzle and the heat transfer enhancement ribs on the target plate naturally becomes more accurate. Taking these circumstances into account, an experimental study was conducted to enhance the heat transfer of the wall jet region of a round impingement jet cooling system. This was done by installing circular ribs or vortex generators (VGs) in the impingement cooling wall jet region. The local heat transfer coefficient was measured using the naphthalene sublimation method, which utilizes the analogy between heat and mass transfer. As a result, it was clarified that, within the ranges of geometries and Reynolds numbers at which the experiments were conducted, it is possible to improve the averaged Nusselt number Nu up to 21% for circular ribs and up to 51% for VGs.

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