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Wyszukujesz frazę "He, Z." wg kryterium: Autor


Tytuł:
Investigation of low-sidelobe beampattern controlling methods for acoustic transmitting array of underwater vehicles
Autorzy:
He, Z.
Shi, Q.
Wu, S.
Powiązania:
https://bibliotekanauki.pl/articles/258624.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater unmanned vehicles
detecting and positioning
acoustic transducer
complex array
low-sidelobe beamforming
Opis:
In underwater unmanned vehicles, complex acoustic transducer arrays are always used to transmitting sound waves to detect and position underwater targets. Two methods of obtaining low-sidelobe transmitting beampatterns for acoustic transmitting arrays of underwater vehicles are investigated. The first method is the boundary element model optimization method which used the boundary element theory together with the optimization method to calculate the driving voltage weighting vector of the array. The second method is the measured receiving array manifold vector optimization method which used the measured receiving array manifold vectors and optimization method to calculate the weighting vector. Both methods can take into account the baffle effect and mutual interactions among elements of complex acoustic arrays. Computer simulation together with experiments are carried out for typical complex arrays. The results agree well and show that the two methods are both able to obtain a lower sidelobe transmitting beampattern than the conventional beamforming method, and the source level for each transmitting beam is maximized in constraint of the maximum driving voltage of array elements being constant. The effect of the second method performs even better than that of the first method, which is more suitable for practical application. The methods are very useful for the improvement of detecting and positioning capability of underwater unmanned vehicles.
Źródło:
Polish Maritime Research; 2017, S 2; 103-110
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of ship rolling motion on take-off aerodynamic characteristics of aircraft
Autorzy:
He, Z.
Sun, X.
Gu, X.
Powiązania:
https://bibliotekanauki.pl/articles/259257.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship rolling motion
ski-jump take-off
Meshless method
WALE turbulence model
aerodynamic characteristics
Opis:
Ship motion is an important factor affecting on the safety of ski-jump take-off. The simplified frigate ship SFS1 was numerically simulated, and the results were compared with the experimental data, the feasibility of the calculation method was verified; Meshless method and WALE turbulence model were used to simulate the process of aircraft skijump take-off, aerodynamic characteristics under different rolling conditions during the aircraft ski-jump take-off process were presented. The results showed that: the influence of ship rolling motion on lift coefficient, drag coefficient and pitching moment was small, side force and rolling moment were greatly affected by rolling motion; the region of downwash with the maximum speed was about 10 m from the bow; the safety of ski-jump take-off was greatly affected when aircraft was close to the bow within 20 m.
Źródło:
Polish Maritime Research; 2018, S 2; 23-29
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mass transfer process of leaching weathered crust elution-deposited rare earth ore with magnesium salts
Autorzy:
Chen, Z.
Zhang, Z.
He, Z.
Chi, R.
Powiązania:
https://bibliotekanauki.pl/articles/110343.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mass transfer
magnesium salts
theory plate
weathered crust elution-deposited rare earth ore
Opis:
In order to optimize the leaching process of weathered crust elution-deposited rare earth ore with magnesium salts, the influence of different flow rate, concentration of magnesium ions, initial pH of magnesium salts solution and experimental temperature on the mass transfer process of rare earth and aluminum was investigated in the case of using magnesium salts as leaching agent. The relationship between the flow rate μ and the HETP (Height Equivalent of Theoretical Plate) is in accordance with the Van Deemter equation when magnesium salts were used as leaching agent. The optimum condition for rare earth and aluminum were 0.4 cm3/min of flow rate and 0.2 mol/dm3 of magnesium ion concentration of magnesium sulfate, magnesium chloride and magnesium nitrate respectively. Under this condition the mass transfer efficiency of rare earth and aluminum with three kinds of magnesium salts follow the order of Mg(NO3)2>Mg(Cl)2>MgSO4. High temperature contributes to improving the mass transfer efficiency of rare earth and aluminum. Magnesium nitrate as the leaching agent can get the highest leaching mass transfer efficiency of rare earth and magnesium sulfate as the leaching agent can make the impurity leaching and mass transfer efficiency of Al is the lowest.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 1004-1013
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-resolved measurement of the compression displacement fields on the front and rear surfaces of an epoxy sample
Autorzy:
Zhang, W.
Dong, B.
He, Z.
Xie, S.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174399.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
depth-resolved measurement
compression displacement field
wavenumber-scanning interferometry
epoxy
Opis:
Compression is one of the typical parameters measured in material mechanics. In this research, the compression displacement fields on the front and rear surfaces of an epoxy sample are measured by using a tilt depth-resolved wavenumber-scanning Michelson interferometer. The light source is a distributed feedback laser diode, the wavenumber of which can be modulated to about 1.017 × 104 m–1 by the temperature without mode hopping. A random-sampling Fourier transform is designed to evaluate the phase differences before and after the applied loads. Experimental results show that the depth-resolved measurement of the compression displacement field is of high accuracy. It can be used to analyze force propagation inside resin-based composites.
Źródło:
Optica Applicata; 2018, 48, 2; 311-323
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of HMX via Nitrolysis of DPT Catalyzed by Acidic Ionic Liquids
Autorzy:
He, Z.
Luo, J.
Lu, Ch.
Xu, R.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/358495.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
DPT
HMX
nitrolysis
ionic liquid
Opis:
The direct nitrolysis of DPT to synthesize HMX with ionic liquids (ILs) as catalysts was investigated. The results showed that [Et3NH] HSO4 was the best catalyst among 18 ILs used and the yield of HMX was up to 61% against 45% without IL. The ILs could be effciently recovered by simple distillation and extraction after reaction without any apparent loss of catalytic activity even after 10 times recycling.
Źródło:
Central European Journal of Energetic Materials; 2011, 8, 2; 83-91
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity
Autorzy:
Peng, Q.
Cao, W.
Zhou, W.
He, Z.
Jiang, W.
Chen, W.
Powiązania:
https://bibliotekanauki.pl/articles/358757.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nitramine explosives
electrostatic hazards
resistivity
charging characteristics
electrostatic discharge sensitivity
Opis:
The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 3; 755-769
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A velocity measurement method based on scaling parameter estimation of chaotic system
Autorzy:
Liu, L.
Hu, J.
He, Z.
Han, C.
Li, H.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/220466.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal processing
parameter estimation
chaos
synchronization
Opis:
In this paper, we propose a new method of measuring the target velocity by estimating the scaling parameter of a chaos-generating system. First, we derive the relation between the target velocity and the scaling parameter of the chaos-generating system. Then a new method for scaling parameter estimation of the chaotic system is proposed by exploiting the chaotic synchronization property. Finally, numerical simulations show the effectiveness of the proposed method in target velocity measurement.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 275-281
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogical and chemical characteristics of the lead-zinc tailing and contaminated soil from the mine tailing pond in Hunan Province (China)
Autorzy:
Li, C.
Zeng, L.
Fu, J.
Chen, J.
He, J.
He, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110442.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mineralogical characteristics
chemical fractionation
remediation
Opis:
The mineralogical and chemical characteristics of heavy metals in tailings and soils is an imperative for potential ecological risk assessment of metals to environment and heavy metals pollution prevention and control. The lead-zinc tailing and contaminated soil in and near the tailing pond were sampeled from a mine tailing pond in Hunan province (China), in which the chemical composition, phase composition and thermal behavior of tailing and soil were investigated. Furthermore, the petrography of lead-zinc tailing and chemical fractionations of Pb and Zn in the contaminated soil were studied in details. The mineral phases of lead-zinc tailing were galena, pyrite, chalcopyrite, sphalerite, quartz and fluorite, as distinguished by the reflected light microscopy and further proofed by the scanning electron microscope-energy dispersive spectrometer under the back scattered electron mode. Chemical fractionations were carried out by the European Community Bureau of Reference (BCR) sequential extraction procedure for Pb and Zn in the soil and the mild acido-soluble (F1), reducible (F2), oxidizable (F3), and residual (F4) fractions were 5.90, 75.24, 4.90 and 13.96% for Pb, and 47.74, 34.06, 9.59 and 8.61% for Zn, respectively. Subsequently, the individual contamination factor (ICF) of Pb and Zn were calculated as 6.16 and 10.61, respectively. The DTPA-available content of Pb and Zn in the contaminated soil were 39.9 and 170.7 mg·kg-1, respectively. The study provided a base for selecting remediation strategies in the studied area.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1133-1147
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving Triggering Characteristics for a Surface-Flashover Triggered Vacuum Switch
Autorzy:
He, Z.
Wang, L.
Li, F.
Yao, W.
Dong, M.
Zhao, C.
Powiązania:
https://bibliotekanauki.pl/articles/1807889.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.Vp
52.75.Kq
52.25.Mq
Opis:
A surface-breakdown triggered vacuum switch with parallel disk electrodes and semiconductor surface flashover trigger electrode has many advantages, it is easy to be triggered and machined. The resistance of the trigger gap has been increased in terms of modifying the thickness of the semiconductor layer and improving coating process technology. The trigger gap resistance, trigger voltage and trigger waveforms were experimentally tested. The results show that the triggering characteristics can be improved by increasing the trigger resistance.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1019-1021
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Survival potential of Phytophthora infestans sporangia in relation to environmental factors and late blight occurrence
Autorzy:
Olanya, O.M.
Anwar, M.
He, Z.
Larkin, R.P.
Honeycutt, C.W.
Powiązania:
https://bibliotekanauki.pl/articles/65009.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
survival
Phytophthora infestans
sporangia
environmental factor
late blight
occurrence
climate variability
potato
tomato
Opis:
Potato is an important crop globally and late blight (Phytophthora infestans) often results in severe crop loss. The cost for late blight control can be in excess of $210 million in the United States. We utilised a non-parametric density distribution analysis of local temperature (T) and relative humidity (RH), from 2005 to 2009, to assess and validate sporangia survival potential using survival model and late blight risks during the potato cropping season at Presque Isle, in the northern part of the state of Maine, USA. Modelbased analyses showed that ambient temperatures of 3−30°C and RH values of 45−100% were conducive for sporangia survival. Disease outbreaks and risk periods coincided with a high sporangia survival probability (15−35%). Due to the omission of solar radiation (SR) in the computation of survival potential in previous research, we applied a Cox proportional model to estimate the probability of sporangia survival [i.e. hazard at a specific time H(t)] as a function of baseline hazard (H0) and the influencing parameters. The model is: H(t) = H0(t) × exp(0.067ET + 0.138T + 0.083RH + 0.001SR) where ET is exposure time. The survival model indicated that RH (β = 0.083) and T (β = 0.138) were significant (p < 0.05) factors in sporangia survival in comparison to SR (β = 0.001). The hazard ratio, indicative of sporangia survival risk, varied with the predictors. For the unit increase of T, sporangia survival hazard increased by 1.148 times. The Cox model and sporangia hazard probabilities can be used for short-term disease forecasts based on the risk period most conducive for pathogen survival and targeted fungicide applications for optimum late blight management.
Źródło:
Journal of Plant Protection Research; 2016, 56, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of hadronic rescattering on the elliptic flow after the hydrodynamics model
Autorzy:
Ma, G.
Ma, Y.
Sa, B.
Cai, X.
He, Z.
Huang, H.
Long, J.
Shen, W.
Zhong, Ch.
Chen, J.
Zuo, J.
Zhang, S.
Shi, X.
Powiązania:
https://bibliotekanauki.pl/articles/148372.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
elliptic flow
hydrodynamic model
hadronic rescattering
LUCIAE model
Opis:
Abstract A hydrodynamics + hadronic rescattering model is used to simulate Au+Au collisions at 200 GeV and a Cooper-Frye method is adopted for hadronization. The effect of hadronic rescattering on elliptic flow V2 in 20 40% Au+Au collisions at 200 GeV has been investigated. It is found that the hadronic rescattering can suppress elliptic flow V2 and makes an asymmetric system in momentum space tend to be less anisotropic. The suppression effect becomes weak with increasing transverse momentum. In addition, the effect of hadronic rescattering on transverse momentum spectra and anisotropy of hadronic coordinate space is presented.
Źródło:
Nukleonika; 2006, 51,suppl.3; 21-27
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A known-plaintext attack on iterative random phase encoding in fractional Fourier domains
Autorzy:
Yin, F.
He, Q.
Liu, Z.
Powiązania:
https://bibliotekanauki.pl/articles/174043.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image encryption
phase encoding
known-plaintext attack
Opis:
Known-plaintext attack is considered for decrypting the image generated by iterative random phase encoding in fractional Fourier transform domains. The double random phase encoding in Fourier domains is introduced to design the known-plaintext attack procedure. The decryption test is explored without both fractional order and these random phase masks. Some numerical simulations are made to demonstrate the validity of the known-plaintext attack.
Źródło:
Optica Applicata; 2017, 47, 1; 131-139
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving separation efficiency of 6-1 mm coal by introducing vibration energy to dense medium gas-solid fluidized bed
Autorzy:
He, J.
Zhao, Y.
Luo, Z.
Zhao, J.
Duan, C.
He, Y.
Powiązania:
https://bibliotekanauki.pl/articles/110018.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vibration energy
dense medium gas-solid fluidized bed
fluidization quality
density uniformity
separation efficiency
Opis:
Effects of the vibration energy on the fluidization quality and separation performance of dense medium gas-solid fluidized bed were investigated experimentally. The magnetite powder with a wide size range of 0.3-0.074 mm was utilized as the basic medium solids. 6-1 mm fine coal sample from Yongcheng (China) was used to perform the separation experiments. The results indicate that the vibration amplitude A and superficial gas velocity U are greatly significant to the fluidization stability and the density distribution uniformity. Comparing with the bed without vibration, the optimal SP and Sρ values of 0.034 kPa and 0.018 g/cm3 are acquired in vibration bed with the operating factors of A = 1 mm, U = 1.8Umf, f = 15 Hz and Hs = 150 mm. The coal ash content was reduced from 27.84% to 9.50% at a separating density of 1.68 g/cm3 with a probable error E value of 0.505. The separation efficiency of 6-1mm fine coal is effectively improved by introducing vibration energy to dense medium gas-solid fluidized bed. The technology provides a novel approach to achieve high-efficiency separation of 6-1 mm fine coal in the arid and water-shortage areas.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 95-108
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated treatment technology for ground fissures of shallow coal seam mining in the mountainous area of southwestern China: a typical case study
Zintegrowana technologia zapobiegania pęknięciom gruntu w procesie wydobywania płytkich pokładów węgla w górzystym obszarze południowo-zachodnich Chin: typowe studium przypadku
Autorzy:
Zhu, H.
He, F.
Zhang, S.
Yang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/215969.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
wydobywanie węgla
płytki pokład węgla
pęknięcia gruntu
zapadlisko górnicze
zintegrowana technologia zapobiegania
ochrona środowiska
shallow coal seam mining
ground fissures
surface sinkhole
integrated treatment technology
environmental protection
Opis:
This article is the result of treatments on ground fissures for environmental protection and scientific shallow coal seam mining. In the southwestern mining area of China, the traditional longwall mining method has caused a large area of surface sinkhole, ground fissures, vegetation deterioration and disorderly coal gangue. To solve these problems, an integrated treatment technology that includes ground fissure treatment technology and underground backfilled technology was proposed as a solution. The technical principle and technical process were explained in detail; the ground fissure treatment technology involves a “three-step treatment method”, and the underground backfilled technology adopted a strip mining method with backfilling technology. The compression mechanical behavior of backfilled material, including coal gangue, fly ash and ordinary Portland cement, was studied; the mixed ratio of 1:0.3:0.18 was selected. In addition, the vertical stress, vertical displacement and plastic zone of the coal pillar were determined by FLAC3D numerical simulation, and a rational mining scheme of “11 m mining width, 2 m coal pillar width” was determined to be appropriate because of the lower vertical stress, smaller vertical displacement and better supporting capacity of the coal pillar. The monitoring results of ground sinkhole indicated that the maximal ground sinkhole deformation was 17.3 cm, and the deformation showed few changes after this technology was implemented. The treatment capacity of coal gangue and fly ash reached 821.150 t per year, and the vegetation survival rate of the ground fissure treatment area reached 85%. This integrated treatment technology could effectively control ground fissures and surface sinkhole as well as protect the environment.
Artykuł jest opisem zapobiegania pęknięciom gruntu w celu ochrony środowiska, jak również naukowego podejścia do wydobywania płytko zalegających pokładów węgla. W południowo-zachodniej części górniczej Chin tradycyjna, ścianowa metoda wydobywania węgla, powodowała duży obszar powierzchniowego zapadliska, pęknięcia gruntu, pogorszenie stanu wegetacji roślin. W celu rozwiązania tych problemów zaproponowano zintegrowaną technologię zapobiegania, która obejmuje technologię zapobiegania pęknięciom gruntu i podziemną technologię podsadzki. Zasada i proces techniczny zostały szczegółowo opisane; technologia zapobiegania pęknięciom gruntu obejmuje „trójstopniową metodę zabiegu”, a technologia podsadzki zaadoptowała metodę wydobywania węgla pasami. Badano ściśliwość podsadzki, w tym odpadów węglowych, popiołu lotnego i zwykłego cementu portlandzkiego; wybrano mieszaninę o stosunku 1: 0,3: 0,18. Ponadto pionowe naprężenie, pionowe przemieszczenie i strefa plastyczności filaru węglowego zostały określone za pomocą symulacji numerycznej FLAC 3D. Racjonalny schemat wydobycia „szerokość wydobycia 11 m, szerokość filaru węglowego 2 m” był odpowiedni ze względu na niższą wartość naprężenia pionowego, mniejsze pionowe przemieszczenie i lepszą nośność filaru węglowego. Wyniki monitoringu pęknięć gruntu wskazują, że maksymalna deformacja gruntu wynosiła 17,3 cm i wykazała kilka zmian po wdrożeniu tej technologii. Ilość zagospodarowanych odpadów węglowych i popiołu lotnego wynosiła 821 150 Mg na rok, a wskaźnik przeżycia roślinności w obszarze zapobiegania pęknięciom gruntu osiągnął poziom 85%. Ta zintegrowana technologia zapobiegania może skutecznie kontrolować pęknięcia gruntu i deformację powierzchni, a także chronić środowisko.
Źródło:
Gospodarka Surowcami Mineralnymi; 2018, 34, 1; 119-138
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and Calculation of the Initial Ignition Gas Pressure Flow through a Rigid Porous Medium in a 100 mm Ignition Simulator
Autorzy:
Xiao, Z.
Ying, S.
He, W.
Xu, F.
Powiązania:
https://bibliotekanauki.pl/articles/358563.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ignition
ignition simulator
porous media
propellant
modelling
simulation
Opis:
To acquire a better understanding of the early ignition phenomena in a 100 mm ignition simulator loaded with a packed propellant bed, a theoretical model of the ignition gas flow through the rigid porous medium was developed. Three pressure gauges were installed in the lateral side of the ignition simulator for post ignition measurement of the chamber pressure. The pseudo-propellant loaded into the chamber was similar in size to the standard 13/19 single-base cylindrical propellant. It was composed of a rigid ceramic composite with low thermal conductivity. It was assumed that the pseudo-propellant bed was rigid in contrast to the assumption of an elastic porous medium. The calculated pressure values were well verified by the experimental data at a low loading density of the pseudo-propellant bed of 0.18 g•cm-3. However, there was still error between the experimental and the calculated results in the early pressure peak position closest to the ignition primer when the loading density of the pseudo-propellant bed was increased to 0.73 and 1.06 g•cm-3. This error is attributed to the change in local permeability of the pseudo-propellant bed at high loading densities, which is assumed, for ease of modelling, to be constant in the model. These calculations may enable a better understanding of the physical processes of ignition gas flow in an ignition simulator loaded with a pseudo-propellant bed.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 4; 475-489
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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