Effects of Gas Phase and Solid Phase Damping on Instability of Low Frequency Modes in Solid Propellant Rockets

ARS Journal ◽  
1962 ◽  
Vol 32 (3) ◽  
pp. 378-384 ◽  
Author(s):  
OWEN J. DETERS
Keyword(s):  
Gas Phase ◽  
Solid Propellant ◽  
Solid Phase ◽  
Low Frequency ◽  
Phase Damping

Phosphorous and Boron Incorporation and its Effect on Optical Properties of Ge:H and Si0.01Ge0.99:HFilms Deposited by LF PECVD

2012 ◽  
Vol 1372 ◽  
Author(s):  
Nery Delgadillo ◽  
Andrey Kosarev ◽  
Afonso Torres ◽  
Lancelot Garcia ◽  
Brian Gonzales
Keyword(s):  
Gas Phase ◽  
Secondary Ion Mass Spectrometry ◽  
Solid Phase ◽  
Chemical Vapour ◽  
Low Frequency ◽  
Localized States ◽  
Optical Measurements ◽  
Band Tail ◽  
Frequency Plasma ◽  
Secondary Ion

ABSTRACTDeposition conditions that provided low absorption related to both band tail and deep localized states have been found for both materials Ge:H and Si1YGeY:H. Phosphorous incorporation on Si0.01Ge0.99:H films and boron incorporation on Ge:H films were deposited by low frequency plasma-enhanced chemical vapour deposition (LF PECVD). The phosphorous incorporation in solidphase was observed to preferential with the increase of the doping in the gas phase to 2.5 %, and 2.5% to 4% was observed preferential Si0.01Ge0.99 film, boron incorporation in solid phase increase linearly with the increase of the doping gas phase. The content of solid phase was characterized by Secondary ion mass spectrometry (SIMS) profiling. Hydrogen concentration in the films was determined from Fourier transform infrared spectroscopy (FTIR) and SIMS measurements. Optical measurements provided optical gap, localized states, and band tail. A significant reduction of both band tail and deep localized states were observed at boron incorporation in solid phase = 0.004% on Ge:H films and the same were observed at phosphorous incorporation in solid phase = 0.29% on Si0.01Ge0.99:H films.

Validating Soot Models in LES of Turbulent Flames: The Contribution of Soot Subgrid Intermittency Model to The Prediction of Soot Production in an Aero-Engine Model Combustor

2021 ◽  
Author(s):  
Lívia Pereira Tardelli ◽  
Nasser Darabiha ◽  
Denis Veynante ◽  
Benedetta Franzelli
Keyword(s):  
Gas Phase ◽  
Reference Model ◽  
Solid Phase ◽  
Phase Evolution ◽  
Turbulent Flames ◽  
Engine Model ◽  
Aero Engine ◽  
New Strategy ◽  
Parametric Studies ◽  
Soot Model

Abstract Predicting soot production in industrial systems using an LES approach represents a great challenge. Besides the complexity in modeling the multi-scale physicochemical soot processes and their interaction with turbulence, the validation of newly developed models is critical under turbulent conditions. This work illustrates the difficulties in evaluating model performances specific to soot prediction in turbulent flames by considering soot production in an aero-engine combustor. It is proven that soot production occurs only for scarce local gaseous conditions. Therefore, to obtain a statistical representation of such rare soot events, massive CPU resources would be required. For this reason, evaluating soot model performances based on parametric studies, i.e., multiple simulations, as classically done for purely gaseous flames, is CPU high-demanding for sooting flames. Then, a new strategy to investigate modeling impact on the solid phase is proposed. It is based on a unique simulation, where the set of equations describing the solid phase are duplicated. One set accounts for the reference model, while the other set is treated with the model under the scope. Assuming neglected solid phase retro-coupling on the gas phase, the soot scalars from both sets experience the same unique temporal and spatial gas phase evolution isolating the soot model effects from the uncertainties on gaseous models and numerical sensitivities. Finally, the strategy capability is proven by investigating the contribution of the soot subgrid intermittency model to the prediction of soot production in the DLR burner.

Determination of the Force Constants of Non-linear XY2 Molecules in the Gas-Phase by the GF Matrix Method

2004 ◽  
Vol 59 (9) ◽  
pp. 621-622 ◽  
Author(s):  
Fatih Ucun ◽  
Vesile Gūçlü
Keyword(s):  
Gas Phase ◽  
Condensed Phase ◽  
Matrix Method ◽  
Solid Phase ◽  
Force Constants ◽  
Matrix Solution ◽  
The Matrix ◽  
Newton Raphson ◽  
Raphson Method

The force constants of the internal coordinates of nonlinear XY2 molecules in the gas-phase were calculated by using the GF matrix method. The matrix solution was carried out by means a computer program built relative to the Newton-Raphson method and the calculations were listed in a table. The force constants of some molecules in the liquidand solid- phase were also found and compared with these ones, and it was seen that the force constants for more condensed phase are lower as in an agreement with having its lower frequency.

Solid phase characterization and transformation of illite mineral with gas-phase ammonia treatment

2021 ◽  
pp. 127657
Author(s):  
Silvina A. Di Pietro ◽  
Hilary P. Emerson ◽  
Yelena Katsenovich ◽  
Timothy J. Johnson ◽  
Ryan M. Francis ◽  
...  
Keyword(s):  
Gas Phase ◽  
Solid Phase ◽  
Ammonia Treatment ◽  
Phase Characterization

A mathematical model for the flotation of waste activated sludge

2002 ◽  
Vol 46 (11-12) ◽  
pp. 203-208
Author(s):  
K. Fujisaki ◽  
M. El-Zahar
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Gas Phase ◽  
Solid Phase ◽  
Growth Curves ◽  
Vertical Axis ◽  
Waste Activated Sludge ◽  
Flotation Process ◽  
Hindered Settling ◽  
Similar Character

A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated.

Comparison of Doping of Gey Si1-y:H (y>0.95) Films Deposited by Low Frequency PECVD at High (300°C) and Low (160°C) Temperatures

2012 ◽  
Vol 1426 ◽  
pp. 295-299
Author(s):  
Ismael Cosme ◽  
Andrey Kosarev ◽  
Francisco Temoltzi Avila ◽  
Adrian Itzmoyotl
Keyword(s):  
Activation Energy ◽  
Deposition Temperature ◽  
Solid Phase ◽  
Low Frequency ◽  
General Effect ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
High Deposition Temperature ◽  
B Doping ◽  
Low Deposition Temperature

ABSTRACTIn this work we present the results of comparative study n- and p-doping of Ge:H and Ge0.96Si0.04 :H films deposited by LF PECVD at high deposition temperature (HT) Td=300°C and low deposition temperature (LT) Td=160°C. The concentration of boron and phosphorus in solid phase was measured by means of SIMS technique. Such parameters as spectral dependence of absorption coefficient, room temperature conductivity σRT and activation energy Ea for both intrinsic and doped films were obtained. The doping range studied in gas phase was for boron [B]gas= 0 to 0.15% and for phosphorus [P]gas= 0 to 0.2%. In general effect of deposition temperature on P and B doping has been demonstrated. For LT films changes of [P]gas=0.04% to 0.22% resulted in more than 2 orders increasing conductivity and reducing activation energy from Ea=0.28 to 0.16 eV. HT films in the range of [P]gas=0.04% to 0.2% demonstrated saturation of conductivity. HT films showed continuous reducing Ea with increase of [P]gas. In the case of boron doping both HT and LT films had a minimum of conductivity at certain values of [B]gas=0.05% (LT films) and 0.04% (HT films) and related maximums of activation energy Ea(max) at the same doping with Ea(max)=0.47 eV for HT and Ea(max)=0.53 eV for LT films. It suggests a compensation of electron conductivity in un-doped films for low B doping. Further raising [B]gas leads to reducing Ea and the smallest Ea=0.27 eV was obtained at [B]gas=0.18% for HT films and Ea=0.33 eV at [B]gas=0.14% for LH films.

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