Interaction between acoustic waves and the burning surface of solid propellants at elevated temperatures

1972 ◽  
Vol 10 (1) ◽  
pp. 93-97 ◽  
Author(s):  
V. P. Volkov ◽  
Yu. I. Medvedev
Keyword(s):  
Acoustic Waves ◽  
Elevated Temperatures ◽  
Burning Surface ◽  
Solid Propellants

Integration of Electroactive Polymers in MEMS Ultrasonic Sensors

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 000643-000670
Author(s):  
Michael Kranz ◽  
Michael Whitley ◽  
Sharon Sanchez ◽  
Michael Allen
Keyword(s):  
Acoustic Waves ◽  
Elevated Temperatures ◽  
Electroactive Polymers ◽  
Mems Devices ◽  
Multiple Systems ◽  
Electroactive Films ◽  
Machine Failure ◽  
Acoustic Emission Sensors ◽  
Institute Of Technology ◽  
Electrical Impulses

The U.S. Army AMRDEC, Stanley Associates, and the Georgia Institute of Technology are developing spectrally sensitive acoustic emission sensors for the detection of various phenomena of interest in Army missiles and assets. Multiple systems would benefit from monitoring the acoustic spectrum and identifying signatures of interest. These would include monitoring sounds external to Unattended Ground Sensors, looking for specific sounds associated with machine failure in a condition-based maintenance scenario, and identifying items that are impacting each other. Potential device designs employ electroactive polymers to convert acoustic waves into electrical impulses. Many electroactive polymers are, however, not compatible with standard MEMS processing, particularly at elevated temperatures. Piezoelectric films, such as PVDF, require stretching and poling processes to orient the crystal structure. Electret films also require poling to create a permanent polarization, plus discharge occurs at relatively low-temperatures. These types of films are difficult to integrate directly into MEMS devices because of these incompatible processes. The films are therefore added using post-fabrication bonding and assembly processes, thus reducing design flexibility and increasing cost. This paper will present techniques being developed to integrate electroactive polymers directly in MEMS sensors as opposed to performing post-fabrication assembly of electroactive films into sensor structures.

Aluminum agglomeration involving the second mergence of agglomerates on the solid propellants burning surface: Experiments and modeling

2017 ◽  
Vol 136 ◽  
pp. 219-229 ◽  
Author(s):  
Wen Ao ◽  
Xin Liu ◽  
Hichem Rezaiguia ◽  
Huan Liu ◽  
Zhixin Wang ◽  
...  
Keyword(s):  
Burning Surface ◽  
Solid Propellants

Experimental study of the acoustic admittance of the burning surface of composite solid propellants

2011 ◽  
Vol 47 (2) ◽  
pp. 193-199 ◽  
Author(s):  
V. A. Arkhipov ◽  
S. A. Volkov ◽  
L. N. Revyagin
Keyword(s):  
Experimental Study ◽  
Burning Surface ◽  
Solid Propellants ◽  
Acoustic Admittance ◽  
Composite Solid Propellants ◽  
Composite Solid

scholarly journals Correlation of BAW and SAW properties of langasite at elevated temperatures

2015 ◽  
Vol 4 (2) ◽  
pp. 331-340 ◽  
Author(s):  
M. Schulz ◽  
E. Mayer ◽  
I. Shrena ◽  
D. Eisele ◽  
M. Schmitt ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Elevated Temperatures ◽  
Surface Acoustic Waves ◽  
Propagation Loss ◽  
Bulk Acoustic Wave ◽  
Coupling Coefficients ◽  
Data Set ◽  
Acoustic Wave Devices ◽  
Bulk Acoustic Wave Resonators

Abstract. The full set of electromechanical data of langasite (La3Ga5SiO14) is determined in the temperature range from 20 to 900 °C using differently oriented bulk acoustic wave resonators. For data evaluation a physical model of vibration is developed and applied. Thereby, special emphasis is taken on mechanical and electrical losses at high temperatures. The resulting data set is used to calculate the properties of surface acoustic waves. Direct comparison with experimental data such as velocity, coupling coefficients and propagation loss measured using surface acoustic wave devices with two different crystal orientations shows good agreement.

Physical Property and Carbon Black Distribution Impact on Propulsion Efficiency of Paraffin-Based Fuel

2012 ◽  
Author(s):  
Genivaldo P. Santos ◽  
Shirley M. Pedreira ◽  
Pedro T. Lacava
Keyword(s):  
Carbon Black ◽  
Outer Region ◽  
Burning Surface ◽  
Physical Property ◽  
Thin Layers ◽  
Solid Propellants ◽  
Gaseous Oxygen ◽  
Hybrid Propulsion ◽  
Propulsion Efficiency ◽  
Hardness Gradient

In the last decade the hybrid propulsion has been considering as a viable alternative of chemical energy conversion stored in propellants into kinetic energy. This energy is applied in propulsive systems of manned platforms, maneuvering procedures and even in the repositioning process of micro satellites. It is a system of minimum environmental impact and lower cost than traditional systems based on liquid or solid propellants. Paraffin based grains are the hybrid solid fuels appointed as polymeric fuel substitute. The liquid layer formed on the burning surface ensures high regression rate when driven into the flame front. Paraffin grains allow row material recovery and reduce the risk of explosion in the presence of erosive burning. The structure of the grain and the control of the liquefying burning surface layer depend on the additives concentration, such as carbon black, which are added to the fuel matrix during the production process. In the solid propellant paraffin based grain a cylindrical center port developed during the centrifugation tends to concentrate carbon black in the outer region of the grain. During solidification 15% of shrinkage occurs and appears hardness gradient in the longitudinal and transverse directions. The influence of carbon black distribution and hardness gradient in paraffin based grain were evaluated in this work. The study suggests that multiple thin layers grain may generate burning surfaces with hardness and carbon black concentration almost constant. The ballistic properties and propulsion efficiency of a hybrid lab rocket scale with 150 N of thrust were evaluated in the pressure of 2.8 MPa with 140 Kg/(sm2) gaseous oxygen (GOX) mass flux, the results show up the nozzle operation and motor-propellant relationships.

Solid propellants burning enhancement using foil embedding method

2008 ◽  
Vol 112 (1138) ◽  
pp. 725-732
Author(s):  
H. G. Darabkhanid ◽  
N. S. Mehdizadeh
Keyword(s):  
Burning Rate ◽  
Solid Propellant ◽  
Burning Surface ◽  
New Method ◽  
Published Data ◽  
Solid Propellants ◽  
Embedding Method ◽  
Double Base

Abstract The method of metal embedding is widely employed in solid propellant motors with end-burning configuration, thereby significantly improving the burning rate of the propellants. In this study, the cylindrical foil embedding method is applied to double-base solid propellant, as a new method, and the effects of the type and thickness of the foil on the burning surface, as well as the burning rate, are experimentally investigated. It is shown that by using the foil embedding method, the burning characteristics of solid propellants can be improved. Results have been compared to some available data. To the best of the author’s knowledge there are no published data available on this method.

scholarly journals SYNTHESIS OF COOPER CHROMITE (II)

2013 ◽  
Vol 10 (19) ◽  
pp. 30-37
Author(s):  
Jacyra Guimarães FAILLACE ◽  
Marta Eloisa MEDEIROS
Keyword(s):  
Solid Propellant ◽  
Elevated Temperatures ◽  
Raw Materials ◽  
Solid Propellants ◽  
Oxidizing Agent ◽  
Ceramic Method ◽  
Controlled Burning ◽  
Structural Differences ◽  
Ft Ir ◽  
Type Composite

Solid propellants are materials with controlled burning and one of the type used as fuel is solid propellant type composite, NH4ClO4 using as oxidizing agent and certain additives. Among them, stands out as CuCr2O4 accelerator burning (Shen, 1983; West, 1984; Meyer, 1987; Campos et al, 2010). Some of sites are activated by adsorption of reagents and because of this, increase the speed of decomposition of NH4ClO4 (Rastogi, 1978). In the present study, we performed the synthesis of compound CuCr2O4 by the methods of coprecipitation and ceramic, for the purpose of comparing structural differences, thermal and resulting morphological methods employed using the techniques XRD, FT-IR, TGA, DSC, SEM and density determination. The results show the best aspects to the compound synthesized by ceramic method, with higher crystallinity, thermal stability up to 1000°C and morphology more defined, with grains having geometries tetrahedral and octahedral and approximate size of 3750nm, very close to the literature, 3700nm (Smith and Snyder, 1969). However, the ceramic method becomes more expensive to use high purity raw materials, as well as use elevated temperatures for the synthesis of the product, which is used widely in manufacturing propellants for various purposes.

ASYMPTOTIC STABILITY OF TRAVELING WAVES IN SOLID-PROPELLANT COMBUSTION UNDER THERMAL RADIATION

1999 ◽  
Vol 09 (09) ◽  
pp. 1279-1305 ◽  
Author(s):  
MAURIZIO VERRI
Keyword(s):  
Asymptotic Stability ◽  
Thermal Radiation ◽  
Burning Surface ◽  
Traveling Wave Solution ◽  
Combustion Model ◽  
Solid Propellants ◽  
Surface Mass ◽  
Existence And Stability ◽  
Time Periodic Solutions ◽  
The Stability

The steady burning stability of solid propellants under thermal radiation with volumetric absorption is investigated. The combustion model we are dealing with includes the classical assumptions of quasiplanarity of all spatial variations, quasisteadiness of the gas phase and surface reaction. However, the stability analysis requires neither assuming a specific pyrolysis law nor formulating a specific flame submodel as long as the surface mass production and heat feedback satisfy some general properties, which are indeed observed experimentally. The existence of a steady state (traveling wave) solution is proved, and a dispersion relationship for its asymptotic stability is derived by conveniently transforming the problem into an evolution equation in a Banach space. The fully opaque burning surface limit and the case of transparent burning surface with exponential volumetric absorption are examined in details. The resulting stability regions in a proper parameter space are given and, finally, existence and stability of bifurcating time-periodic solutions are discussed.

ANALYSIS OF ULTRASONIC SIGNALS FOR MEASURING BURNING RATES OF SOLID PROPELLANTS

2008 ◽  
Vol 22 (11) ◽  
pp. 1117-1122
Author(s):  
HYUN-TAEK OH ◽  
HAK-JOON KIM ◽  
SUNG-JIN SONG ◽  
SUN-FEEL KO ◽  
IN-CHUL KIM ◽  
...  
Keyword(s):  
Material Property ◽  
Standard Method ◽  
Pressure Range ◽  
Constant Pressure ◽  
Burning Surface ◽  
Solid Propellants ◽  
Ultrasonic Technique ◽  
Single Test ◽  
Ultrasonic Signals ◽  
Burning Rates

To measure burning rates of solid propellants, the strand burner method is widely adopted as a standard method. The strand burner method measures burning rates under the constant pressure, so it requires a number of measurements to determine the burning rates over all pressure range. However, ultrasonic technique can measure burning rates as a function of pressure in single test, since it performed under a constant volume condition. But, we measured that burning rates by ultrasonic technique have deviation that is bigger than 3% from average one. In this study, to reduce the deviation, we have investigated variation in material property of solid propellants. And then we analyze the relation between variations of the burning rates and material property. Also, we have predicted effects of non-linear burning surface using simulated ultrasonic signals.

Combustion Characteristics of Composite Solid Propellants Containing Different Coated Aluminum Nanopowders

2014 ◽  
Vol 924 ◽  
pp. 200-211 ◽  
Author(s):  
Er Gang Yao ◽  
Feng Qi Zhao ◽  
Si Yu Xu ◽  
Rong Zu Hu ◽  
Hui Xiang Xu ◽  
...  
Keyword(s):  
Burning Rate ◽  
Flame Temperature ◽  
Burning Surface ◽  
Combustion Characteristics ◽  
Solid Propellants ◽  
Nickel Acetylacetonate ◽  
Aluminum Nanopowder ◽  
Composite Solid Propellants ◽  
Burning Rates ◽  
Composite Solid

Aluminum nanopowders coated with oleic acid (nmAl+OA), perfluorotetradecanoic acid (nmAl+PA) and nickel acetylacetonate (nmAl+NA) were prepared. The combustion characteristics of hydroxyl terminated polybutadiene (HTPB) composite solid propellants containing different coated aluminum nanpowders were investigated. The result shows that the burning rate of the propellant sample containing nmAl+NA is the highest at different pressure, the maximum burning rate is up to 26.13 mm·s-1at 15 MPa. The burning rates of propellant samples containing nmAl+OA and nmAl+PA are almost the same at different pressures, and higher than the propellant samples containing untreated aluminum nanopowders only at the pressure range of 10 ~ 15 MPa. The flame brightness of different propellants under different pressure is not the same. The flame brightness is increased with the pressure increasing. The flame center zone brightness of the propellant containing nmAl+PA and nmAl+NA is brighter under 4 MPa, and the brightness of nmAl+NA is the brightest. The surface coating of aluminum nanopowder has little effect on the combustion flame temperature of solid propellant. The burning surface temperature increases with the pressure increasing.

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