Temat: specific impulse - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Ammonium Dodecahydrododecaborate (NH4)2[B12H12]: Hydrogen and Boron Rich Fuel for Jet Propulsion Engines
Autorzy:: Jadhav, Pandurang M.
Patil, Jay
Prasanth, Hima
Rao, Gururaja
Tematy:: jet propulsion
boranes
boron
combustion
specific impulse; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/27788219.pdf Link otwiera się w nowym oknie
Opis:: There is dire need for the exploration of boron (B) substitution in jet propulsion engines for improving their combustion characteristics. In this regard, ammonium dodecahydrododecaborate (NH4)2[B12H12] has been synthesized, characterized and evaluated for its propulsion characteristics. This hydrogen and boron-rich entity was found to be a potential candidate for future applications in propulsion technology.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Investigation of the Radical Nitration of Isooctane Fuel via Nitromethane Propellant
Autorzy:: Bayar, C. C.
Tematy:: nitromethane
isooctane
nitration
specific impulse
Dunning basis sets; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358270.pdf Link otwiera się w nowym oknie
Opis:: The possible radical nitration reactions of isooctane fuel with nitromethane propellant, which is generally used as an additive in fuel formulations, were thermodynamically investigated both at room temperature and at a higher temperature of 691.15 K. The temperature of 691.15 K was chosen because it is the auto-ignition temperature of isooctane and nitromethane and has the potential to mimic better engine conditions. The computational calculations were performed at the theoretical level of DFT UB3LYP/cc-pVDZ. Four different nitration reactions and nitrated products were considered and interpreted in detail. The most and the least favorable nitrations were observed at the primary and secondary carbons of isooctane at 691.15 K, respectively. Four of the designated reactions were endothermic at this temperature. The other outcome of this study was that there was a direct relationship between the thermodynamic tendencies of the considered reactions and the ballistic performances (detonation velocities, detonation pressures, and specific impulses) of their nitrated products. The thermodynamic properties of heats of combustion and deflagration temperatures were calculated via empirical formulations based on the stoichiometry and some other structural parameters of the energetic materials. The results for nitromethane and the nitro-isooctane products were examined.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A thermodynamic study on catalytic decomposition of hydrazine in a space thruster
Autorzy:: Pakdehi, Shahram
Shirvani, Fatemeh
Zolfaghari, Reihaneh
Tematy:: catalytic thruster
hydrazine
ammonia
specific impulse
thermodynamic
analysis; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240211.pdf Link otwiera się w nowym oknie
Opis:: Most satellites stationed in space use catalytic propulsion systems for attitude control and orbit adjustment. Hydrazine is consumed extensively as liquid monopropellant, in the thrusters. Catalytic reactor is the most important section in the catalytic thruster. Ammonia and nitrogen gases are produced as a result of complete catalytic decomposition of hydrazine in the reactor, causing an increase in temperature and a rise in specific impulse. Ammonia is subsequently decomposed, leading to nitrogen and hydrogen gases. Decomposition of ammonia leads to a decrease in temperature, molecular weight and specific impulse. The latter phenomenon is unavoidable. The effect of ammonia decomposition on the reactor temperature, molecular weight of gaseous products and conclusively on specific impulse was studied in this article. At adiabatic state, thermodynamic analysis revealed that the maximum and minimum temperatures were 1655 K and 773 K, respectively. The highest molecular weight was obtained at ammonia conversion of zero and the lowest when ammonia conversion was 100%. The maximum specific impulse (305.4 S) was obtained at ammonia conversion of zero and completely conversion of ammonia, the minimum specific impulse (about 213.7 s) was obtained. For specific impulse, the result of thermodynamic calculation in this work was validated by the empirical results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Optimization of potassium nitrate based solid propellant grains formulation using response surface methodology
Autorzy:: Ogunleye, O O
Hammed, J O
Alagbe, S O
Tematy:: propellant grains
specific impulse
grains performance
combustion instability
geometry; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/102731.pdf Link otwiera się w nowym oknie
Opis:: This study was designed to evaluate the effect of propellant formulation and geometry on the solid propellant grains internal ballistic performance using core, bates, rod and tubular and end-burn geometries. Response Surface Methodology (RSM) was used to analyze and optimize the effect of sucrose, potassium nitrate and carbon on the chamber pressure, temperature, thrust and specific impulse of the solid propellant grains through Central Composite Design (CCD) of the experiment. An increase in potassium nitrate increased the specific impulse while an increase in sucrose and carbon decreased specific impulse. The coefficient of determination (R2) for models of chamber pressure, temperature, thrust and specific impulse in terms of composition and geometry were 0.9737, 0.9984, 0.9745 and 0.9589, respectively. The optimum specific impulse of 127.89 s, pressure (462201 Pa), temperature (1618.3 K) and thrust (834.83 N) were obtained using 0.584 kg of sucrose, 1.364 kg of potassium nitrate and 0.052 kg of carbon as well as bate geometry. There was no significant difference between the calculated and experimented ballistic properties at p < 0.05. The bate grain geometry is more efficient for minimizing the oscillatory pressure in the combustion chamber.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Research Output Software for Energetic Materials Based on Observational Modelling 2.2 (RoseBoom2.2©) - Update to Calculate the Specific Impulse, Detonation Velocity, Detonation Pressure and Density for CHNO Mixtures Using the Supersloth-function
Autorzy:: Klapötke, Thomas M.
Wahler, Sabrina
Tematy:: calculation
EXPLO5
detonation parameter
specific impulse
RoseBoom
mixture; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/59115415.pdf Link otwiera się w nowym oknie
Opis:: RoseBoom2.2© can calculate parameters for CHNO mixtures, automatically minimizing user-input. In the present study, RoseBoom’s© results were compared to 518 EXPLO5 calculations. The new version of RoseBoom© can calculate a variety of parameters for mixtures. The detonation pressure and detonation velocity, and the specific impulse were calculated using different methods. In the present study different approaches for calculating the average sum formula have been evaluated
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Energetic Performances of Solid Composite Propellants
Autorzy:: Lempert, D.
Nechiporenko, G.
Manelis, G.
Tematy:: solid composite propellant
specific impulse
density
combustion temperature
formation enthalpy; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/357962.pdf Link otwiera się w nowym oknie
Opis:: Different kinds of solid composite propellant (SCP) are described. All ways to increase energetic potential of SCP are considered as well as pro et contra of each of these ways. Different kinds of oxidizer (perchlorates of ammonium, hydroxylammonium, and hydrazinium; ammonium salt of dinitramine; other saltlike and molecular oxidizers) are under consideration. The main principles creation of SCP formulation with optimal characteristics in the context of their concrete purpose are discussed, e.g. for rockets with considerably low ratio propellant volume/empty construction mass (V/M lower than 1 Litr/kg or so) the ballistic effectiveness may be increased with the replacement of aluminum by high-dense zirconium or zirconium hydride. Possibilities for creation of special SCP formulations for application at the far space, e.g. for Mars exploration are discussed as well.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Quantitative Variations Resulting from the Gradual Replacement of NO2 with NF2-fragments in Energetic Materials
Autorzy:: Lempert, D. B.
Dorofeenko, E. M.
Tematy:: difluoramines
solid composite propellants
specific impulse
optimal formulation
boron
decaborane; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358600.pdf Link otwiera się w nowym oknie
Opis:: A thermodynamic analysis of the energetic parameters and the combustion products of model energetic systems based on the mixture tetranitromethane + tetra(difluoramino)methane as oxidizer, and combustible components (either polyethylene, or carbon, or boron, or decaborane) has been accomplished. The optimal ratios between the components for achieving the maximal specific impulse have been found. The nature of the combustion products, the dependence of their distribution on the percentage of the components, and how the distribution of the combustion products influences the specific impulse value, have been studied.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: A Theoretical Study of Polyethylene Glycol Polynitrates as Potential Highly Energetic Plasticizers for Propellants
Autorzy:: Wang, Guixiang
Xu, Yimin
Zhang, Wenjing
Gong, Xuedong
Tematy:: polyethylene glycol polynitrates
density functional theory
density
specific impulse
stability; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358877.pdf Link otwiera się w nowym oknie
Opis:: Polyethylene glycol polynitrates may be used as plasticizers in propellants. In this study, ten derivatives of ethylene glycol dinitrate were investigated using the density functional theory method. The fitted densities (ρ’exp.) were obtained and were very close to the experimental values. The detonation properties were predicted using the modified Kamlet-Jacobs equations and the specific impulse (Is) was evaluated according to the largest exothermic principle. A new indicator, K = Is · ρ’exp., is proposed to evaluate the energetic characteristics of the plasticizers. Thermal stability is discussed by calculating the bond dissociation energies or energy barriers. The O−NO2 bond is the trigger bond for all of the compounds studied. Considering the energetic properties and stability, diethylene glycol tetranitrate, triethylene glycol hexanitrate, tetraethylene glycol octanitrate, pentaethylene glycol decanitrate and hexaethylene glycol dodecanitrate are potential energetic plasticizers for solid propellants. The influences of the −O−CH2−CH2− and −O−CH(ONO2)−CH(ONO2)− groups are also discussed, which will be helpful for the design of new highly energetic plasticizers by modifying the structures as required.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Effect of Some Inorganic Nitrate Salts on the Ignition Delay Time of DMAZ-IRFNA and DMAZ-WFNA Bi-propellants
Autorzy:: Pakdehi, S. G.
Shirzadi, B.
Tematy:: DMAZ
liquid oxidizers
ignition delay time
inorganic nitrate salts
specific impulse; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358187.pdf Link otwiera się w nowym oknie
Opis:: Dimethylaminoethyl azide (DMAZ) is a good replacement for the hydrazine group in the space industry. However, it has a relatively long ignition delay time with the liquid oxidizer, white fuming nitric acid (WFNA), and is nonhypergolic with inhibited red fuming nitric acid (IRFNA). In this article, the ignition delay times of DMAZ-WFNA and DMAZ-IRFNA bi-propellants were reduced by the addition of some inorganic nitrate salts, such as NH4NO3, KNO3, NaNO3, AgNO3 and LiNO3, to the liquid oxidizers. The results showed that WFNA containing 0.1 wt.%, 0.3 wt.% and 0.5 wt.% of LiNO3 reduced the ignition delay time of DMAZ-WFNA from 88 ms to 18 ms, 14 ms and 8 ms, respectively. The same percentages of LiNO3 caused the nonhypergolic DMAZ-IRFNA bi-propellant to have ignition delay times of 42 ms, 34 ms and 22 ms, respectively. Moreover, calculations indicated that the addition of LiNO3 to both oxidizers did not have a significant affect on the specific impulse of the bi-propellants. Consequently LiNO3 could be an appropriate additive for the reduction of the ignition delay times of DMAZ-WFNA and DMAZ-IRFNA bi-propellants.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Studies on the High Performance Characteristics of an Aluminized Ammonium Perchlorate Composite Solid Propellant Based on Nitrile Butadiene Rubber
Autorzy:: Sudhir, Singh
Sidharth, Raveendran
Dhirendra, Kshirsagar R.
Gupta, Manoj
Chetan, Bhongale
Tematy:: composite solid propellant
dibutyl phthalate
high density specific impulse
nitrile-butadiene rubber
pot life
spreadibility
yield stress; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/27787902.pdf Link otwiera się w nowym oknie
Opis:: n the present study, a high performance composite solid propellant formulation was prepared based on nitrile butadiene rubber (NBR) and dibutyl phthalate (DBP) plasticizer, which has a longer pot life and high density specific impulse. The developed cost effective novel binder system was prepared with readily available raw materials (NBR and DBP). The formulation of the composition was performed by varying the content of the NBR/DBP binder in the range of 14-20%. The rocket performance characteristics were determined theoretically using PROPEP and compared with those of an HTPB based propellant. The rheological, mechanical, physical, ballistic and thermal properties of the NBR/DBP propellant were studied and compared with literature data for similar compositions based on an HTPB/dioctyl adipate (DOA) binder. The yield stress was determined by spreadibilty measurements, and indicated the superiority of this binder based propellant over existing composite propellants. It was concluded that following decreasing the content of the NBR/DBP binder in the propellant from 20 to 14%: in the range 58.83-78.45 bar (5.883-7.845 MPa), the pressure index increased from 0.159 to 0.371, – at 68.64 bar (6.864 MPa), the burning rate increased from 4.10 to 6.54 mm/s, but the theoretical specific impulse value did not change significantly (258.0259.8 s), – the tensile strength and E-modulus increased from 6.03 to 9.88 (0.591-0.969) to and from 18.00 to 75.00 kgf/cm2 (1.765 to 7.355 MPa), respectively. Moreover, a DSC and TGA study indicated a lower decomposition temperature for the NBR/DBP propellant compared to the HTPB propellant. The NBR/DBP propellant exhibited a pot life more than double that of a conventional HTPB/ DOA based propellant.
Dostawca treści:: Biblioteka Nauki

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