Thermostructural Analyses Supporting the Design of the HYPROB Heat Sink Subscale Breadboard

2014 ◽  
Author(s):  
M. Ferraiuolo ◽  
A. Martucci ◽  
F. Battista ◽  
D. Ricci
Keyword(s):  
Heat Sink ◽  
Structural Integrity ◽  
Specific Impulse ◽  
Thermal Analyses ◽  
High Energy ◽  
Life Cycles ◽  
Heat Fluxes ◽  
Point Of View ◽  
Rocket Engines ◽  
Combustion Enthalpy

Today’s rocket engines regeneratively cooled using high energy cryogenic propellants (e.g. LOX and LH2, LOX and LCH4) play a major role due to the high combustion enthalpy (10–13.4 kJ/kg) and the high specific impulse of these propellants. In the frame of the HYPROB/Bread project, whose main goal is to design build and test a 30 kN regeneratively cooled thrust chamber, a breadboard has been conceived in order to: • investigate the behavior of the injector that will be employed in the full scale final demonstrator, • to obtain a first estimate of the heat flux on the combustion chamber for models validation, • to implement a “battleship” chamber for a first verification of the stability of the combustion The breadboard is called HS (Heat Sink) and it is made of CuCrZr (Copper Chromium Zirconium alloy), Inconel 718 and TZM (Titanium Zirconium Molybdenum alloy). The aim of the present paper is to illustrate the thermostructural design conducted on the breadboard by means of a Finite Element Method code taking into account the viscoplastic behavior of the adopted materials. An optimization process has been carried out in order to keep the structural integrity of the breadboard maximizing the life cycles of the component. Heat fluxes generated by combustion gases have been evaluated by means of CFD quick analyses, while convection and radiation with the external environment have not been considered in order to be as conservative as possible from a thermostructural point of view. Transient thermal analyses and static structural analyses have been performed by means of ANSYS code adopting an axisymmetric model of the chamber. These analyses have demonstrated that the Breadboard can withstand the design goal of 3 thermo-mechanical cycles with a safety factor equal to 4 considering a firing time equal to 3 seconds.

Common Currency for System Integration of High Intensity Energy Subsystems

2011 ◽  
Author(s):  
David M. Pratt ◽  
David J. Moorhouse
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
High Intensity ◽  
Waste Heat ◽  
Integrated Approach ◽  
High Energy ◽  
Heat Fluxes ◽  
System Level ◽  
Level Energy ◽  
Common Currency

Aerospace vehicle design has progressed in an evolutionary manner, with certain discrete changes such as turbine engines replacing propellers for higher speeds. The evolution has worked very well for commercial aircraft because the major components can be optimized independently. This is not true for many military configurations which require a more integrated approach. In addition, the introduction of aspects for which there is no pre-existing database requires special attention. Examples of subsystem that have no pre-existing data base include directed energy weapons (DEW) such as high power microwaves (HPM) and high energy lasers (HEL). These devices are inefficient, therefore a large portion of the energy required to operate the device is converted to waste heat and must be transferred to a suitable heat sink. For HPM, the average heat load during one ‘shot’ is on the same order as traditional subsystems and thus designing a thermal management system is possible. The challenge is transferring the heat from the HPM device to a heat sink. The power density of each shot could be hundreds of megawatts. This heat must be transferred from the HPM beam dump to a sink. The heat transfer must occur at a rate that will support shots in the 10–100Hz range. For HEL systems, in addition to the high intensity, there are substantial system level thermal loads required to provide an ‘infinite magazine.’ Present models are inadequate to analyze these problems, current systems are unable to sustain the energy dissipation required and the high intensity heat fluxes applied over a very short duration phenomenon is not well understood. These are examples of potential future vehicle integration challenges. This paper addresses these and other subsystems integration challenges using a common currency for vehicle optimization. Exergy, entropy generation minimization, and energy optimization are examples of methodologies that can enable the creation of energy optimized systems. These approaches allow the manipulation of fundamental equations governing thermodynamics, heat transfer, and fluid mechanics to produce minimized irreversibilities at the vehicle, subsystem and device levels using a common currency. Applying these techniques to design for aircraft system-level energy efficiency would identify not only which subsystems are inefficient but also those that are close to their maximum theoretical efficiency while addressing diverse system interaction and optimal subsystem integration. Such analyses would obviously guide researchers and designers to the areas having the highest payoff and enable departures from the evolutionary process and create a breakthrough design.

Analysis of the performance of electrodynamic tethers with autonomous electron generation

2020 ◽  
Author(s):  
P.M. Bechasnov
Keyword(s):  
Magnetic Field ◽  
Specific Impulse ◽  
High Energy ◽  
Rocket Engines ◽  
Jet Engines ◽  
Electron Generation ◽  
Rocket Thrust ◽  
Electrodynamic Tethers ◽  
Rapid Deceleration ◽  
A Current

Currently, electric rocket engines have largely reached the efficiency limits determined by the principle of rocket thrust. Electrodynamic tethers, interacting with an external magnetic field and actually being jet engines, are devoid of such restrictions. However, their thrust is limited by the concentration of the external plasma and depends on its fluctuations. The paper is the first to propose to create a current in the tether by propellant ionization, receiving a large thrust from a relatively short tether and a strong magnetic field deflecting charged cosmic particles. The numerical analysis showed that the length of the tether of hundreds of meters near the Earth provides a specific impulse of up to hundreds of kilometers per second and its proper acceleration of the power plant at a level of 0.01 m / s2, as well as protection of the central region of the tether from particles with an energy of more than 1 MeV. This makes it possible to consider it for maneuvering satellites with practically no restrictions on the delta-V, for performing fast high-energy inter-orbital flights and for radiation protection of a high-latitude orbital station. In the future, such a tether can be used for rapid deceleration of orbital objects, launching into geostationary orbit, interplanetary transfers and protection of objects from charged particles. The study describes possible areas of application and directions for further research of the concept of such a tether.

Three-Dimensional Multiphysics Analyses of a CPU Integrated Thermal Heat Sink

2010 ◽  
Author(s):  
Maher Al-Dojayli ◽  
Ellen Chan ◽  
Sunny Leung ◽  
Hani Naguib ◽  
Francis Dawson ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Heat Sink ◽  
Conjugate Heat Transfer ◽  
Structural Integrity ◽  
Natural Frequencies ◽  
Thermal Analyses ◽  
Three Dimensional ◽  
Flow Speed ◽  
Wall Structure ◽  
Heat Generation Rate

Recent advances in electronic packaging have led to small, lightweight and highly efficient heat sink designs. Some of these attempts are aiming to integrate the heat sink with the packaging wall structure. In this paper, a three-dimensional multiphysics numerical model is developed for the integrated heat sink to carry out CFD and thermal analyses, stress analyses due to thermal expansion and modal analyses. Finite volumes were used to model the conjugate heat transfer (CHT) for the coupled fluid-structure fields representing the air and heat sink fin walls and base, respectively. In this analysis, both natural and forced convection analyses were considered. The predicted temperature distribution was then used to calculate the mechanical stresses due to thermal expansion, using finite elements. Lastly, modal analyses were conducted to calculate the natural frequencies of the model. The effect of varying the source heat generation rate, air flow speed, and some geometry features such as number of fins and fin’s height on the performance and structural integrity of the assembly have been studied.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

EFFECT OF BORON ON THE COMBUSTION CHARACTERISTICS OF METALLIZED HIGH-ENERGY MATERIALS

2020 ◽  
Author(s):  
A. Korotkikh ◽  
◽  
I. Sorokin ◽  
◽  
Keyword(s):  
Specific Impulse ◽  
Equilibrium Composition ◽  
Combustion Products ◽  
High Energy ◽  
Combustion Characteristics ◽  
Solid Propellants ◽  
Energy Materials ◽  
High Energy Materials ◽  
Condensed Combustion Products ◽  
Active Fuel Binder

The paper presents the results of thermodynamic calculations of the effect of pure boron additives on combustion characteristics of high-energy materials (HEM) based on ammonium perchlorate, ammonium nitrate, active fuel-binder, and powders of aluminum Al, titanium Ti, magnesium Mg, and boron B. The combustion parameters and the equilibrium composition of condensed combustion products (CCPs) of HEM model compositions were obtained with thermodynamic calculation program “Terra.” The compositions of solid propellants with different ratios of metals (Al/B, Ti/B, Mg/B, and Al/Mg/B) were considered. The combustion temperature Tad in a combustion chamber, the vacuum specific impulse J at the nozzle exit, and the mass fraction ma of the CCPs for HEMs were determined.

An Integral Heat Sink for Cooling Microelectronic Components

1993 ◽  
Vol 115 (3) ◽  
pp. 284-291 ◽  
Author(s):  
S. H. Bhavnani ◽  
C.-P. Tsai ◽  
R. C. Jaeger ◽  
D. L. Eison
Keyword(s):  
Heat Sink ◽  
Silicon Surface ◽  
Numerical Study ◽  
High Heat ◽  
Heat Fluxes ◽  
Silicon Surfaces ◽  
Source Surface ◽  
Mouth Size ◽  
Severe Constraint ◽  
Boiling Incipience

Liquid immersion cooling is rapidly becoming the mechanism of choice for the newest generation of supercomputers. Miniaturization at both the chip and module level places a severe constraint on the size of the heat sink employed to dissipate the high heat fluxes generated. A study was conducted to develop a surface that could augment boiling heat transfer from silicon surfaces under these constraints. The surface created consists of reversed pyramidal features etched directly on to the silicon surface. Experiments were conducted in a saturated pool of refrigerant-113 at atmospheric pressure. The inexpensive crystallographic etching techniques used to create the enhanced features are described in the paper. The main characteristics of interest in the present study were the incipient boiling superheat and the magnitude of the temperature overshoot at boiling incipience. Results were obtained for test sections with various cavity densities, and compared with data for the smooth untreated surface. It was found that incipient boiling superheat was reduced from a range of 27.0–53.0° C for the untreated silicon surface, to a range of 2.5–15.0° C for the enhanced surfaces. The overshoot also decreased considerably; from about 12.0–18.0° C for two classes of untreated surfaces, to a range of 1.5–5.3° C for the enhanced surfaces. The values of the incipient boiling superheat, and those of the overshoot decreased with a decrease in cavity mouth size. Two ratios of heat source surface area to the area of the enhanced surface were studied. The overshoot values obtained for these surfaces were compared with those observed for some commonly used enhanced surfaces. An elementary numerical study was conducted to estimate the magnitude of heat spreading.

Hydoroil-Based Micro Pin Fin Heat Sink

2006 ◽  
Author(s):  
Ali Kosar ◽  
Chih-Jung Kuo ◽  
Yoav Peles
Keyword(s):  
Heat Sink ◽  
Hydraulic Performance ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
Pin Fins ◽  
Micro Pin Fins

An experimental study on thermal-hydraulic performance of de-ionized water over a bank of shrouded NACA 66-021 hydrofoil micro pin fins with wetted perimeter of 1030-μm and chord thickness of 100 μm has been performed. Average heat transfer coefficients have been obtained over effective heat fluxes ranging from 4.0 to 308 W/cm2 and mass velocities from 134 to 6600 kg/m2s. The experimental data is reduced to the Nusselt numbers, Reynolds numbers, total thermal resistances, and friction factors in order to determine the thermal-hydraulic performance of the heat sink. It has been found that prodigious hydrodynamic improvement can be obtained with the hydrofoil-based micro pin fin heat sink compared to the circular pin fin device. Fluid flow over pin fin heat sinks comprised from hydrofoils yielded radically lower thermal resistances than circular pin fins for a similar pressure drop.

scholarly journals Cooling Performance of Heat Sinks Used in Electronic Devices

2018 ◽  
Vol 171 ◽  
pp. 02003
Author(s):  
Ibrahim Mjallal ◽  
Hussein Farhat ◽  
Mohammad Hammoud ◽  
Samer Ali ◽  
Ali AL Shaer ◽  
...  
Keyword(s):  
Heat Sink ◽  
Electronic Devices ◽  
Heat Fluxes ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Passive Cooling ◽  
Short Term ◽  
Cooling Systems ◽  
Thermal Output ◽  
Electrical Devices

Existing passive cooling solutions limit the short-term thermal output of systems, thereby either limiting instantaneous performance or requiring active cooling solutions. As the temperature of the electronic devices increases, their failure rate increases. That’s why electrical devices should be cooled. Conventional electronic cooling systems usually consist of a metal heat sink coupled to a fan. This paper compares the heat distribution on a heat sink relative to different heat fluxes produced by electronic chips. The benefit of adding a fan is also investigated when high levels of heat generation are expected.

scholarly journals Metals and Alloys Additives as Enhancer for Rocket Propulsion: A Review

2021 ◽  
Vol 90 (1) ◽  
pp. 1-9
Author(s):  
Izham Izzat Ismail ◽  
Norhuda Hidayah Nordin ◽  
Muhammad Hanafi Azami ◽  
Nur Azam Abdullah
Keyword(s):  
Specific Impulse ◽  
Flame Temperature ◽  
High Energy ◽  
Combustion Efficiency ◽  
High Energy Density ◽  
Regression Rate ◽  
High Entropy ◽  
Rocket Propulsion ◽  
Wide Range ◽  
Metal Additives

A rocket's engine usually uses fuel and oxygen as propellants to increase the rocket's projection during launch. Nowadays, metallic ingredients are commonly used in the rocket’s operation to increase its performance. Metallic ingredients have a high energy density, flame temperature, and regression rate that are important factors in the propulsion process. There is a wide range of additives have been reported so far as catalysts for rocket propulsion. The studies show that the presence of metal additives improves the regression rate, specific impulse and combustion efficiency. Herein, the common energetic additives for rocket propulsion such as metal and light metals are reviewed. Besides the effect of these energetic particles on the regression behaviors of base (hybrid) fuel has been exclusively discussed. This paper also proposed a new alloy namely high entropy alloys (HEAs) as a new energetic additive that can potentially increase the performance of the rocket propellant system.

scholarly journals Research Progress and Key Issues of Hydrodebenzylation of Hexabenzylhexaazaisowurtzitane (HBIW) in the Synthesis of High Energy Density Material Hexanitrohexaazaisowurtzitane (HNIW)

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 409
Author(s):  
Xiaofei Tang ◽  
Rui Zhu ◽  
Tianjing Shi ◽  
Yu Wang ◽  
Xiaochen Niu ◽  
...  
Keyword(s):  
Energy Density ◽  
High Performance ◽  
Research Effort ◽  
Specific Impulse ◽  
Cost Effective ◽  
High Energy ◽  
High Energy Density ◽  
Research Progress ◽  
Fourth Generation ◽  
Key Issues

High energy density materials (HEDM) are the subject of an extensive research effort in relation to the use of these compounds as components of rocket propellants, powders, and formulations of high-performance explosives. Hexanitrohexaazaisowurtzitane (HNIW, i.e., CL-20) has received much attention in these research fields for its specific impulse, burning rate, ballistics, and detonation velocity. In this paper, the development and performances of the explosives from the first to the fourth generation are briefly summarized, and the synthesis status of the fourth-generation explosive, HNIW, is reviewed. The key issues that restrict the development of industrial amplification synthesis of HNIW are analyzed, and the potential directions of development are proposed. It is pointed out that to synthesize new and efficient catalysts is the key to making the cost-effective manufacturing of CL-20 a reality.

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