Comparative Assessment of Thermal Protective Characteristics of Metal and Ceramic Shields of Flow Paths of High-Temperature Gas Dynamic Facilities

2020 ◽  
pp. 52-75
Author(s):  
V.A. Tovstonog
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Thermal Protection ◽  
Modern Technology ◽  
Flow Path ◽  
Comparative Assessment ◽  
Working Fluid ◽  
Gas Dynamic ◽  
Heat Shields ◽  
Ramjet Engines

In modern technology, gas dynamic facilities with a flow path of a high-temperature working fluid are widely used. Their effectiveness largely depends on the maximum achievable temperature, which is to a great extent determined by the heat resistance of structural materials and thermal protection systems of the most heat-stressed structural units. Most often, mass transfer thermal protection methods using the coolant of fuel components are used in such plants. However, in some gas dynamic facilities, such as high-speed ramjet engines, the use of such methods is only sufficient to maintain an acceptable temperature level for the elements of the flow path itself. As for the thermal protection of the enclosing structural elements which are adjacent to the path, it can be provided with either uncooled screens or heat-insulating linings. The study gives a comparative assessment of the temperature regime and characteristics of alternative types of heat shields

scholarly journals Editorial: Ultra High Temperature Ceramics for Aerospace Applications

2010 ◽  
Vol 3 (1) ◽  
pp. 9-9
Author(s):  
Raffaele Savino
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Thermal Protection ◽  
Space Vehicles ◽  
Component Level ◽  
Ultra High Temperature Ceramics ◽  
Thermal Protection Systems ◽  
Protection Systems ◽  
The Subject ◽  
Ultra High Temperature

Improved interest in ultra-high-temperature ceramics (UHTCs) is being animating the scientific community. This emerging attention is driven by the demand of developing re-usable hot structures as thermal protection systems of aerospace vehicles, able to re-enter in planetary atmospheres at relatively high speed (order of 8-11 Km/s). In contrast to traditional blunt capsules or Shuttle-like vehicles, characterised by poor gliding capabilities and complex thermal protection systems, the future use of UHTCs opens new horizons for the development of spaceplanes with slender fuselage noses and sharp wing leading edges. Advanced aerodynamic configurations reduce the vehicles drag, enhance the vehicles performances, due to a larger manoeuvrability resulting in larger down range, cross range and abort windows, and reduce electromagnetic interferences and communications black-out. Analysis has shown that materials with temperature capability approaching 2000°C and above will be required for these space vehicles, but the state of the art Reinforced Carbon-Carbon (RCC) material, currently used on the Space Shuttle, have maximum use temperatures of approximately 1650°C. The articles collected in this issue provide state-of-art scientific advancements on the subject with particular attention to the potential technological applications. The papers specifically deal with research studies on monolithic ceramic materials, composed primarily of Zirconium and Hafnium Diborides with different additives. The activities are carried out at materials level, with furnace or arc-jet testing, or include developments of UHTC-based hot structures at sub-component level. In the latter case, ultra-high temperature ceramic prototype structures have been developed and tested with embedded structural health monitoring systems. I want to thank all the article contributors for their manuscripts. I hope they will be useful for future basic and applied researches on the subject.

INTRODUCTION TO C3HARME PROJECT

2021 ◽  
Author(s):  
LUCA ZOLI ◽  
DILETTA SCITI
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Thermal Protection ◽  
Weight Ratio ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Thermal Protection Systems ◽  
Protection Systems ◽  
Ultra High Temperature

High-speed aviation brings many challenges, one being the materials used ensure the aircraft and rockets travelling at hypersonic speed arrive at their destination safely. Control surfaces and thermal protection systems for vehicles flying at Mach 5 or above must withstand extremely hot temperatures and intense mechanical vibrations at launch, during cruising and re-entry into the Earth’s atmosphere. UHTCMCs (Ultra-High Temperature Ceramic Matrix Composites) belong to a new subclass of ceramic matrix composites (CMCs) with superior properties in terms of structural and chemical stability at elevated temperature and erosion/ablation resistance keeping excellent strength-to-weight ratio, thermal shock resistance and adequate damage tolerance. They are the latest potential candidates for thermal protection systems (TPSs), able to outperform bulk ultra-high temperature ceramics (UHTCs). C3HARME is a 4-years EU funded program involving 12 European partners from 6 countries focused on the design, fabrication and testing of UHTCMCs for nearzero erosion nozzles and near-zero ablation TPS tiles. C3harme will look at different technologies coming from the science of bulk ceramics and CMCs and combine them to find out new approaches for their manufacturing. Novel theoretical models and testing methodologies are necessary to characterize properly these materials. This talk will summarize some of the findings and advances of the program, with special emphasis on the innovative approaches that we have implemented.

Dynamic Modelling of Small Scale and High Temperature ORC System Using Simulink and CoolProp

2020 ◽  
Author(s):  
Radheesh Dhanasegaran ◽  
Antti Uusitalo ◽  
Teemu Turunen-Saaresti
Keyword(s):  
High Temperature ◽  
Dynamic Model ◽  
High Speed ◽  
Waste Heat ◽  
Fluid Pressure ◽  
Dynamic Modelling ◽  
Working Fluid ◽  
Small Scale ◽  
Condensation Process ◽  
Feed Pump

Abstract In the present work, a dynamic model has been developed for the small-scale high-temperature ORC experimental test rig at the LUT University that utilizes waste heat from a heavy-duty diesel engine exhaust. The experimental facility consists of a high-speed Turbogenerator, heat exchanger components such as recuperator, condenser, and evaporator with a pre-feed pump to boost the working fluid pressure after the condensation process constituting a cycle. The turbogenerator consists of a supersonic radial-inflow turbine, a barske type main-feed pump, and a permanent magnet type generator components connected on a single shaft. Octamethyltrisiloxane (MDM) is the chosen organic working fluid in this cycle. Matlab-Simulink environment along with the open-source thermodynamic and transport database Cool-Prop has been chosen for calculating the thermodynamic properties of the dynamic model. A functional parameter approach has been followed for modeling each block component by predefined input and output parameters, aimed at modeling the performance characteristics with a limited number of inputs for both design and off-design operations of the cycle. The dynamic model is validated with the experimental data in addition to the investigation of exhaust gas mass flow regulation that establishes a control strategy for the dynamic model.

scholarly journals Gas-Dynamic Foil Bearings Application in High-Speed Turbines

2015 ◽  
Vol 27 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Bolesław Giemza ◽  
Emil Nowiński ◽  
Marek Domański
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Foil Bearings ◽  
Gas Dynamic ◽  
Aviation Technology ◽  
Turbo Machinery

Abstract Authors present the general characteristics of the gas-dynamic foil bearings in the paper. The short analysis of the application and possibilities of using gas-dynamic bearings in turbo machinery, especially in the aspect of aviation technology were described. Authors also pointed out possible directions of development and gas-dynamic foil bearings application in high-speed turbines, especially working in high temperature.

scholarly journals Development verification of coatings made from porous ceramic-matrix composite materials

2018 ◽  
Vol 224 ◽  
pp. 03019 ◽  
Author(s):  
Sergey Reznik ◽  
Pavel Prosuntsov ◽  
Konstantin Mikhaylovskiy
Keyword(s):  
High Temperature ◽  
Porous Ceramic ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Operating Conditions ◽  
Gas Dynamic ◽  
Before And After ◽  
Heat Shields ◽  
Carbon Ceramic ◽  
High Temperature Gas

The paper presents methodology and results of tests conducted for porous carbon ceramic specimens on a high-temperature gas dynamic facility to simulate real operating conditions for heat shields. The structure of the materials before and after tests is compared.

scholarly journals Ежекторний детонаційний двигун на екологічно чистих компонентах палива

2021 ◽  
pp. 20-27
Author(s):  
Олександра Валеріївна Сосновська ◽  
Олександр Євгенович Золотько ◽  
Олена Василівна Золотько ◽  
Віталій Васильович Столярчук
Keyword(s):  
High Speed ◽  
Specific Impulse ◽  
Flow Path ◽  
Working Fluid ◽  
Tvd Scheme ◽  
Time Interval ◽  
Numerical Implementation ◽  
Thrust Coefficient ◽  
Detonation Engine ◽  
Ejector Nozzle

The subject of research in the article is engines operating on the detonation principle of converting the energy of the working fluid. In recent years, there has been an exponential growth in the number of scientific papers devoted to detonation engines, and the most promising direction is the study of detonation engines with an ejector nozzle (EN). The work aims to obtain the results of studies of the defining characteristics of a detonation engine with an ejector nozzle. The main tasks are the scientific analysis of the working process of the pulse detonation engine with EN; modeling of working processes occurring in the flow path of the engine; numerical implementation of a mathematical model and a computational experiment. Methods, for the numerical implementation of the model of a detonation engine with an ejector, a finite-difference TVD scheme of the second order of accuracy was used. According to the results of the work performed, we observe two regions on the pressure curves, within which the pressure remains unchanged for a certain time interval (pressure plateau). An increase in the length of the ejector leads to an increase in the duration of the stage of the outflow of detonation products from the flow path of the engine, an increase in the added mass of atmospheric air, and contributes to a significant increase in the specific impulse of thrust. The value of the thrust impulse was obtained by integrating the excess pressure on the traction wall over time. Conclusions. The scientific novelty is as follows. The change in pressure overtime on the traction wall of the detonation chamber when using cylindrical EHs of different lengths was investigated by the method of numerical simulation. The value of the thrust coefficient of the ejector nozzle for the starting conditions is obtained. The studies carried out in this work are aimed at analyzing the operating mode of a promising propulsion system and are aimed at modeling the gas-dynamic processes of a pulsed detonation engine with an ejector to obtain the data necessary for preliminary design, consideration of alternative design options, and an operational assessment of the possible characteristics of an engine with an ejector. The main advantages of the engine are the ultra-high-speed of energy release in the detonation process, which leads to an increase in the efficiency of the thermodynamic cycle, simplification and cost reduction of the design, and a significant gain in in-flight performance.

Trends in the development of flexible thermal protection systems for modern aircraft

2020 ◽  
pp. 10-21
Author(s):  
V. G. Babashov ◽  
◽  
N. M. Varrik ◽  
Keyword(s):  
High Temperature ◽  
Thermal Protection ◽  
Heat Removal ◽  
Operating Conditions ◽  
Passive Protection ◽  
Thermal Protection Systems ◽  
Heat Protection ◽  
Protection Systems ◽  
Protected Surface ◽  
Flexible Panels

The emergence of new types of space and aviation technology necessitates the development of new types of thermal protection systems capable of operating at high temperature and long operating times. There are several types of thermal protection systems for different operating conditions: active thermal protection systems using forced supply of coolant to the protected surface, passive thermal protection systems using materials with low thermal conductivity without additional heat removal, high-temperature systems, which are simultaneously elements of the bearing structure and provide thermal protection, ablation materials. Heat protection systems in the form of rigid tiles and flexible panels, felt and mats are most common kind of heat protecting systems. This article examines the trends of development of flexible reusable heat protection systems intended for passive protection of aircraft structural structures from overheating.

ALX ALLOY

Alloy Digest ◽  
1963 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Speed ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cobalt Base

Abstract ALX is a composition of nonferrous materials with a cobalt base containing chromium, tungsten and carbon. This alloy is commonly supplied in the cast-to-shape form, having an as-cast hardness of Rockwell C60-62 and requiring no further heat treatment. ALX is also supplied as cast tool bit material and is useful where conventional high-speed steels or carbides do not function effectively. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, forming, heat treating, and machining. Filing Code: Co-35. Producer or source: Allegheny Ludlum Corporation.

CYCLOPS M4

Alloy Digest ◽  
1978 ◽  
Vol 27 (7) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Abrasion Resistance ◽  
High Speed ◽  
Heat Treating ◽  
Heavy Duty ◽  
Maximum Hardness ◽  
Temperature Performance ◽  
Sharp Edges ◽  
Normal Carbon

Abstract CYCLOPS M4 is a deep-hardening steel that was developed to utilize the excellent abrasion resistance that results from higher-than-normal carbon and vanadium contents in the molybdenum-tungsten family of high-speed steels. It is recommended for heavy-duty cutting operations and for sharp edges for fine cuts. Cyclops M4 should always be used at or near maximum hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-335. Producer or source: Cyclops Corporation.

CRUCIBLE CPM REX 121

Alloy Digest ◽  
2001 ◽  
Vol 50 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
High Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
Heat Treating ◽  
Maximum Hardness ◽  
Temperature Performance ◽  
Red Hardness ◽  
Cutting Speeds

Abstract CPM Rex 121 is a super high-speed steel with significantly higher wear resistance and red hardness than other high-speed steels. It is best suited for applications requiring high cutting speeds. It may provide an alternative to carbide where carbide cutting edges are too fragile. The annealed hardness is approximately 350-400 HB, and maximum hardness is approximately 72 HRC. This datasheet provides information on composition, physical properties, microstructure, hardness, and elasticity as well as fracture toughness. It also includes information on high temperature performance and wear resistance as well as heat treating and surface treatment. Filing Code: TS-591. Producer or source: Crucible.

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