Hydrocarbon Fuel Cooling Technologies for Advanced Propulsion

1997 ◽  
Vol 119 (2) ◽  
pp. 344-351 ◽  
Author(s):  
D. R. Sobel ◽  
L. J. Spadaccini
Keyword(s):  
Heat Sink ◽  
High Speed ◽  
Hydrocarbon Fuel ◽  
High Heat ◽  
Operating Conditions ◽  
Zeolite Catalysts ◽  
Reaction Products ◽  
Fuel Conversion ◽  
Heat Exchanger Design ◽  
Tube Reactor

Storable hydrocarbon fuels that undergo endothermic reaction provide an attractive heat sink for future high-speed aircraft. An investigation was conducted to explore the endothermic potential of practical fuels, with inexpensive and readily available catalysts, under operating conditions simulative of high-speed flight applications. High heat sink capacities and desirable reaction products have been demonstrated for n-heptane and Norpar 12 fuels using zeolite catalysts in coated-tube reactor configurations. The effects of fuel composition and operating condition on extent of fuel conversion, product composition, and the corresponding endotherm have been examined. The results obtained in this study provide a basis for catalytic-reactor/heat-exchanger design and analysis.

scholarly journals Hydrocarbon Fuel Cooling Technologies for Advanced Propulsion

1995 ◽  
Author(s):  
David R. Sobel ◽  
Louis J. Spadaccini
Keyword(s):  
Heat Sink ◽  
High Speed ◽  
Hydrocarbon Fuel ◽  
High Heat ◽  
Operating Conditions ◽  
Zeolite Catalysts ◽  
Reaction Products ◽  
Fuel Conversion ◽  
Heat Exchanger Design ◽  
Tube Reactor

Storable hydrocarbon fuels that undergo endothermic reaction provide an attractive heat sink for future high-speed aircraft. An investigation was conducted to explore the endothermic potential of practical fuels, with inexpensive and readily available catalysts, under operating conditions simulative of high-speed flight applications. High heat sink capacities and desirable reaction products have been demonstrated for n-heptane and Norpar 12 fuels using zeolite catalysts in coated-tube reactor configurations. The effects of fuel composition and operating condition on extent of fuel conversion, product composition and the corresponding endotherm have been examined. The results obtained in this study provide a basis for catalytic-reactor/heat-exchanger design and analysis.

scholarly journals Cooling Performance of a Novel Circulatory Flow Concentric Multi-Channel Heat Sink with Nanofluids

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 647 ◽  
Author(s):  
Ravindra Jilte ◽  
Mohammad H. Ahmadi ◽  
Ravinder Kumar ◽  
Vilas Kalamkar ◽  
Amirhosein Mosavi
Keyword(s):  
Heat Sink ◽  
Volume Fraction ◽  
Removal Rate ◽  
Heat Removal ◽  
High Heat ◽  
Operating Conditions ◽  
Bottom Surface ◽  
Outlet Temperature ◽  
Cooling Performance ◽  
Heat Rejection

Heat rejection from electronic devices such as processors necessitates a high heat removal rate. The present study focuses on liquid-cooled novel heat sink geometry made from four channels (width 4 mm and depth 3.5 mm) configured in a concentric shape with alternate flow passages (slot of 3 mm gap). In this study, the cooling performance of the heat sink was tested under simulated controlled conditions.The lower bottom surface of the heat sink was heated at a constant heat flux condition based on dissipated power of 50 W and 70 W. The computations were carried out for different volume fractions of nanoparticles, namely 0.5% to 5%, and water as base fluid at a flow rate of 30 to 180 mL/min. The results showed a higher rate of heat rejection from the nanofluid cooled heat sink compared with water. The enhancement in performance was analyzed with the help of a temperature difference of nanofluid outlet temperature and water outlet temperature under similar operating conditions. The enhancement was ~2% for 0.5% volume fraction nanofluids and ~17% for a 5% volume fraction.

Effect of Gravitational Orientation on Flow Boiling of Water in 1054 × 197 µm Parallel Minichannels

2004 ◽  
Author(s):  
Satish G. Kandlikar ◽  
Prabhu Balasubramanian
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Flow Boiling ◽  
High Heat ◽  
Operating Conditions ◽  
Microgravity Environment ◽  
High Heat Flux ◽  
Two Phase ◽  
Mass Fluxes ◽  
Heat Transfer Degradation

Microchannels and minichannels are being considered for high heat flux applications under microgravity environment in space missions. An experimental study is undertaken to determine the effect of gravitational orientation on flow boiling characteristics of water in a set of six parallel minichannels, each 1054 μm wide by 197 μm deep and 63.5 mm long with a hydraulic diameter of 333 μm. Three orientations — horizontal, vertical downflow and vertical upflow — are investigated under identical operating conditions of heat and mass fluxes. High-speed images are obtained to reveal the detailed two-phase flow structure and liquid-vapor interactions. The experimental data and high speed flow visualization indicate that compared to the horizontal case, the flow becomes less chaotic for vertical upflow, while the reversed flow becomes more pronounced in vertical downflow case. The resulting in increase in the back-flow is responsible for channel-to-channel flow maldistribution and heat transfer degradation. From the heat transfer data it is concluded that the performance of the tested channels under microgravity environment will be similar to the horizontal flow case.

Heat Transer Enhancement Using Flow-Induced Vibration of a Microfin Array

2000 ◽  
Author(s):  
Jeung Sang Go ◽  
Geunbae Lim ◽  
Hayong Yun ◽  
Junghyun Lee ◽  
Inseob Song ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Flow Velocity ◽  
Surface Area ◽  
Heat Sink ◽  
High Speed ◽  
Fluid Velocity ◽  
Heat Removal ◽  
High Heat ◽  
Thermal Engineering ◽  
Flow Induced Vibration

Abstract Advanced notebook computers are facing thermal engineering challenges from both the high heat generation with rapid performance improvement and the reduction of the available heat removal surface area. Efficient and compact cooling technology is desired to provide the reliable operation of the microelectronic devices. This paper investigates the feasibility of heat transfer enhancement in laminar flow using the flow-induced vibration of a microfin array without the additional consumption of battery power or the extension of heat removal surface area. The microfins are initially bent due to the residual stress difference. A high speed motion analyzer records the flow-induced vibration of the microfin array. Increase in flow velocity provides larger vibrating deflection and higher frequency of the microfin. We measure the thermal resistances to evaluate the thermal performance of the microfin heat sink and compare them with those of the plain-wall heat sink. For the fluid velocity of 4.4m/s, the thermal resistance of the microfin array heat sink is measured to be 4.45°C/W and that of the plain-wall heat sink 4.69°C/W, which indicates 5.5% cooling enhancement. At the flow velocity of 5.5m/s, the thermal resistance of the microfin array heat sink decreases by 11.5%.

scholarly journals ДОСЛІДЖЕННЯ ЯКОСТІ ДОСЛІДНОГО ЖАРОМІЦНОГО НІКЕЛЕВОГО БЕЗРЕНІЕВОГО СПЛАВА ЗМІ-М5 (ЖС32Б-ВІ)

2018 ◽  
pp. 88-94
Author(s):  
Евгений Владимирович Милонин ◽  
Павел Евгениевич Малиновский ◽  
Сергей Валентинович Гайдук
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Nickel Alloys ◽  
High Speed ◽  
High Heat ◽  
Operating Conditions ◽  
Alloying Elements ◽  
Time To Failure ◽  
Directional Crystallization ◽  
Experimental Heat

One of the features of the operation of ground installations in contrast to aircraft engines is the much lower quality of the fuel used. As a result, the combustible materials used contain much more aggressive (sulfur and other) contaminants, which leads to the non-strength characteristics of the material of cast parts of the hot tract, and their ability to resist high-temperature corrosion in the operating conditions of the unit.Analysis of the effect of alloying elements on the properties of high-temperature nickel alloys for ground installations leads to the conclusion that it is expedient to completely eliminate expensive rhenium from their composition and replace it with an increased content of relatively less expensive alloying elements, which simultaneously provide sufficiently high heat resistance and necessary resistance against high-temperature corrosion.The composition, structure and properties of cast samples obtained from the experimental heat-resistant rhenium-free alloy ZMI-M5 (ZhS32B-VI), by high-speed directional crystallization were studied.The alloy ZMI-M5 (ZhS32B-VI) according to the content of elements (with the exception of tungsten content) complies with the requirements of the temporary technical conditions.Mechanical properties, as well as long-term strength at the 975 ºC test temperature and 30 kgf/mm2 loading meet the requirements of the temporary technical conditions.The time to failure at a temperature of 1000 ºC under a load of 28 kgf/mm2 is unstable, ranging from 21 to 55 hours. The decrease in the tр values at 1000 ºC is probably due to the crystallographic direction of the samples. It is established that higher tр values (55 h) have samples with a crystallographic orientation.The microstructure of the samples after heat treatment is characteristic of high-temperature nickel alloys of the ZhS type. Heat treatment in this regime did not lead to a significant eutectic (γ-γ) phase reduction in the metal.The experimental alloy ZMI-M5 (ZhS32B-VI) does not contain rhenium, it has a significantly lower cost, while it provides mechanical properties at the level of the industrial alloy ZhS32-VI and can be used for ground use gas turbine installations blades manufacturing by directional crystallization.

An Experimental Study on the Effect of Gravitational Orientation on Flow Boiling of Water in 1054×197μm Parallel Minichannels

2005 ◽  
Vol 127 (8) ◽  
pp. 820-829 ◽  
Author(s):  
Satish G. Kandlikar ◽  
Prabhu Balasubramanian
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
High Speed ◽  
Flow Boiling ◽  
High Heat ◽  
Operating Conditions ◽  
Microgravity Environment ◽  
High Heat Flux ◽  
Two Phase ◽  
Heat Transfer Degradation

Microchannels and minichannels are being considered for high heat flux applications under microgravity environment in space missions. An experimental study is undertaken to determine the effect of gravitational orientation on flow boiling characteristics of water in a set of six parallel minichannels, each 1054μm wide by 197μm deep and 63.5mm long with a hydraulic diameter of 333μm. Three orientations—horizontal, vertical downflow, and vertical upflow—are investigated under identical operating conditions of heat and mass fluxes. High-speed images are obtained to reveal the detailed two-phase flow structure and liquid-vapor interactions. The experimental data and high speed flow visualization indicate that compared to the horizontal case, the flow becomes less chaotic for the vertical upflow case, while the reversed flow becomes more pronounced in the vertical downflow case. The resulting increase in the backflow is responsible for channel-to-channel flow maldistribution and heat transfer degradation. From the heat transfer data it is concluded that the performance of the tested channels in a microgravity environment will be similar to the horizontal flow case.

Investigation of On-Chip Hot Spot Cooling Using Microchannel Heat Sink

2013 ◽  
Vol 455 ◽  
pp. 466-469
Author(s):  
Yun Chuan Wu ◽  
Shang Long Xu ◽  
Chao Wang
Keyword(s):  
Heat Flux ◽  
Heat Sink ◽  
Hot Spots ◽  
Hot Spot ◽  
High Heat ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Three Dimensional Model ◽  
Spot Cooling ◽  
On Chip

With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.

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