scholarly journals Experimental Investigation of the Effectiveness of Jet Impingement Cooling System on the Pressure Side of the Turbine Blade

2021 ◽  
Vol 84 (1) ◽  
pp. 33-42
Author(s):  
Nur Farah Hanis Kamalulzaman ◽  
Nurul Farhanah Azman ◽  
Mohamad Nor Musa ◽  
Syahrullail Samion
Keyword(s):  
Nusselt Number ◽  
Turbine Blade ◽  
Cooling System ◽  
Jet Impingement ◽  
Side Surface ◽  
Diameter Ratio ◽  
Pressure Side ◽  
Model Surface ◽  
Air Velocity ◽  
Impingement Cooling

The effectiveness of the jet impingement system on the turbine blade pressure side has been experimentally investigated. The effects of height-to-diameter ratio and air velocity on the effectiveness of jet impingement were studied. Experiments was performed under varying height-to-diameter ratios (H/D = 5, 10, 15, 20) where the distance from the nozzle to the pressure side surface ranged from 20, 40, 60 and 80 mm with a constant nozzle diameter of 4 mm. The Nusselt number is calculated to determine the cooling effect of the pressure side model surface. Experiments were also performed at varying air velocity at 6.4 m/s and 12.6 m/s. The findings revealed that there was no direct relationship between Nusselt number and H/D ratio where the optimum cooling impact at a velocity of 6.4 m/s was found to be at H/D=15, whereas at a velocity of 12.6 m/s it was found to be at H/D=5. The findings also reveal that the amount of Nusselts rises as the air velocity increases.

Jet Impingement Cooling System on the Pressure Side of Turbine Blade

2014 ◽  
Vol 695 ◽  
pp. 503-507
Author(s):  
Mohamad Nor Musa ◽  
Mohamed Izhar Mohamed Khalid
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Turbine Blade ◽  
Nozzle Exit ◽  
Cooling System ◽  
Jet Impingement ◽  
Pressure Side ◽  
Cooling Effectiveness ◽  
Impingement Cooling ◽  
Surface Distance

This study is to investigate the effectiveness of jet impingement cooling system on the turbine blade pressure side. The objective of this study is to determine the mass blowing rate referred to Reynolds number and the nozzle exit to surface distance which will produce the highest cooling effectiveness which will be shown as Nusselt number. A model of CF6-50 blade is made from mild steel and an experiment to study the jet impingement cooling effectiveness on the pressure side of turbine blade is conducted. The parameters that are included in the experiment are the Reynolds number, Re = 646, 1322, 1970 and 2637; and nozzle exit to surface distance, s/d = 4.0 cm, 8.0 cm and 12.0 cm. The results obtained are calculated and graphs for each experiment are made. The result shows that the jet impingement cooling effectiveness are the highest at where the nozzle is pointed and the cooling effectiveness decreases as it travels further away on the blade. The theory of jet impingement cooling is presented and the several factors that affect jet impingement cooling are also discussed.

Effectiveness of Jet Impingement Cooling System on Convex Surface

2016 ◽  
Vol 819 ◽  
pp. 74-77
Author(s):  
Mohamad Nor Musa ◽  
Mohamad Faizal Fauzi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Convex Surface ◽  
Cooling System ◽  
Jet Impingement ◽  
Impingement Cooling ◽  
Reynolds Number Increase ◽  
Number Increase

Jet impingement is one of cooling method used in order to achieve high heat transfer coefficient and widely used in industry applications such as drying of textile and film, glass and plastic sheets, cooling of electronic equipment, and heat treatment of metals. In this research, it focused on the effectiveness of the jet impingement cooling system on the convex surface based on mass blowing rate and nozzle exit to surface parameters. The scope of experiment research encompasses are convex surface made of aluminum alloy and diameter 12.5cm. For mass blowing rate parameters, it use ʋjet = 1.98m/s, 3.03m/s, 4.97m/s and 6.00m/s which has Reynolds number range from 643 until 1946. Nozzle exit to surface distance,s/d = 4.0, 8.0 and 12.0. In this experiment model, a major components that involved are a compressor, nozzle, convex surface model, K thermocouple and heater. For the result of the experiment, it is based on the data obtain through a heat transfer coefficient and Nusselt number which the plotted graph focus on the space spacing and Reynolds number parameters. For the graph Nusselt number versus s/d at stagnation point c/d=0, it shown that when the Reynolds number increase, the Nusselt number also increase. In term of effectiveness, the s/d=12.0 has a good effectiveness jet impingement cooling system. For the graph of Nusselt number versus Reynolds at stagnation point, c/d=0, as Reynolds number increase, the Nusselt number increase too. From this experiment the better cooling effect is at Reynolds number, Re=1946. Thus, it can conclude that, effectiveness for jet impingement cooling system on the convex surface occurs at the highest Reynolds number.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

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.

Impingement Cooling by Multiple Asymmetric Orifice Jets

2021 ◽  
Author(s):  
Chunyu Zhang ◽  
Yanyan Liu ◽  
Taahir Bhaiyat ◽  
Sjouke Schekman ◽  
Tian Jian Lu ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Thermal Characteristics ◽  
Jet Impingement ◽  
Diameter Ratio ◽  
Impingement Cooling ◽  
Blunt Edge ◽  
Surrounding Fluid ◽  
Target Spacing

Abstract This study presents impingement cooling from a flat plate by multiple asymmetric jets. Such jets are discharged through blunt-edge inline orifice holes with a thickness-to-diameter ratio of t/Dj = 0.5 and a jet-to-jet spacing of T/Dj = 4.0, at the Reynolds number of 20,000. Firstly, fluidic features are established both in free exit and with impingement, at varying short target spacing (e.g., H/Dj = 4.0). Secondly, thermal characteristics of the jet impingement are elucidated. Results demonstrate that, due to a skewed incidence of the coolant stream upstream of concave orifice holes, the resulting multiple orifice jets are asymmetric and skewed relative to the orifice axis. These results mimic multiple fluidically inclined jets. However, asymmetric entrainment that takes place causes faster mixing with the surrounding fluid at rest as well as faster decay of momentum. This shows more effective cooling from a flat plate for the relatively short H/Dj range than conventional symmetric orifice and nozzle jets.

Multiphase Submerged Jet Impingement Cooling Utilizing Nanostructured Plates

2012 ◽  
Author(s):  
Ebru Demir ◽  
Ali Kosar ◽  
Turker Izci ◽  
Osman Yavuz Perk ◽  
Muhsincan Sesen ◽  
...  
Keyword(s):  
Cooling System ◽  
Electronic Devices ◽  
Control Sample ◽  
Heat Removal ◽  
Jet Impingement ◽  
Impinging Jets ◽  
Copper Plate ◽  
Impingement Cooling ◽  
Surface Morphologies ◽  
Aluminum Base

An experimental setup is designed to simulate the heat dissipated by electronic devices and to test the effects of nanostructured plates in enhancing the heat removal performance of jet impingement systems in such cooling applications under boiling conditions. Prior experiments conducted in single phase have shown that such different surface morphologies are effective in enhancing the heat transfer performance of jet impingement cooling applications. In this paper, results of the most recent experiments conducted using multiphase jet impingement cooling system will be presented. Distilled water is propelled into four microtubes of diameter 500 μm that provide the impinging jets to the surface. Simulation of the heat generated by miniature electronic devices is simulated through four aluminum cartridge heaters of 6.25 mm in diameter and 31.75 mm in length placed inside an aluminum base. Nanostructured plates of size 35mm×30mm and different surface morphologies are placed on the surface of the base and two thermocouples are placed to the surface of the heating base and the base is submerged into deionized water. Water jets generated using microtubes as nozzles are targeted to the surface of the nanostructured plate from a nozzle to surface distance of 1.5 mm and heat removal characteristics of the system is studied for a range of flow rates and heat flux, varying between 107.5–181.5 ml/min and 1–400000 W/m2, respectively. The results obtained using nanostructured plates are compared to the ones obtained using a plain surface copper plate as control sample and reported in this paper.

Effects of Nanoparticle Shape on Slot-Jet Impingement Cooling of a Corrugated Surface With Nanofluids

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Fatih Selimefendigil ◽  
Hakan F. Öztop
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Average Nusselt Number ◽  
Volume Fraction ◽  
Jet Impingement ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Corrugated Surface ◽  
Nanoparticle Shapes

Numerical study of jet impingement cooling of a corrugated surface with water–SiO2 nanofluid of different nanoparticle shapes was performed. The bottom wall is corrugated and kept at constant surface temperature, while the jet emerges from a rectangular slot with cold uniform temperature. The finite volume method is utilized to solve the governing equations. The effects of Reynolds number (between 100 and 500), corrugation amplitude (between 0 and 0.3), corrugation frequency (between 0 and 20), nanoparticle volume fraction (between 0 and 0.04), and nanoparticle shapes (spherical, blade, brick, and cylindrical) on the fluid flow and heat transfer characteristics were studied. Stagnation point and average Nusselt number enhance with Reynolds number and solid particle volume fraction for both flat and corrugated surface configurations. An optimal value for the corrugation amplitude and frequency was found to maximize the average heat transfer at the highest value of Reynolds number. Among various nanoparticle shapes, cylindrical ones perform the best heat transfer characteristics in terms of stagnation and average Nusselt number values. At the highest solid volume concentration of the nanoparticles, heat transfer values are higher for a corrugated surface when compared to a flat surface case.

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