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Aeroelastic analysis of guided hypersonic launch vehicles
, Article Scientia Iranica ; Volume 11, Issue 1-2 , 2004 , Pages 26-36 ; 10263098 (ISSN) ; Assadian, N ; Sharif University of Technology
Sharif University of Technology
2004
Abstract
This study is concerned with the general motion of a guided flexible launch vehicle idealized as a non-uniform beam under continuous thrust action. The governing equations of motion are derived following the Lagrangian approach and generalized coordinates. The rigid motion consists of the conventional vehicle velocities (rotational and translative), whereas the elastic motion, introduced through modal substitution, represents the vehicle local lateral and transverse displacements relative to a mean body axis system. A complete simulation routine has been developed, which allows for investigation of the influence of variuos vibrational forcing functions, local stiffness changes and the...
An analytical and experimental study of a hybrid rocket motor
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, Issue. 13 , December , 2014 , pp. 2475-2486 ; ISSN: 09544100 ; Soltani, M. R ; Sharif University of Technology
Abstract
The hybrid rocket motor is a kind of chemical propulsion system that has been recently given serious attention by various industries and research centers. The relative simplicity, safety and low cost of this motor, in comparison with other chemical propulsion motors, are the most important reasons for such interest. Moreover, throttle-ability and thrust variability on demand are additional advantages of this type of motor. In this paper, the result of an internal ballistic simulation of hybrid rocket motor in a zero-dimensional form is presented. Further to validate the code, an experimental setup was designed and manufactured. The simulation results are compared with the experimental data...
Transient conduction prediction in nozzle assembly of solid rocket motors
, Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 4 , 2007 , Pages 2333-2337 ; 1563478900 (ISBN); 9781563478901 (ISBN) ; Tahsini, A. M ; Sharif University of Technology
2007
Abstract
Transient heat-up of a solid propellant rocket structure during motor burning time is studied, numerically. The solid phase energy equation coupled with unsteady compressible flow equations are used in this simulation. The flow-field equations are discretized and solved using upwind Roe's scheme. The results show that heat transfer from the gas phase boundaries has negligible effect on internal ballistics behavior. On the other hand, the results are suitable for a thermal stresses analysis in the chamber case and are consequently valuable from structural design viewpoints
Rapid depressurization dynamics of solid propellant rocket motors
, Article 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, 8 July 2007 through 11 July 2007 ; Volume 8 , 2007 , Pages 7871-7879 ; 1563479036 (ISBN); 9781563479038 (ISBN) ; Farshchi, M ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2007
Abstract
Transient internal ballistics of a solid propellant rocket motor during rapid depressurization due to opening of an auxiliary nozzle for active thrust termination has been considered in this work. Prediction of thrust termination and reversing dynamics is required for successful stage separation in multi-stage rockets. Quasi one-dimensional unsteady Euler equation with a transient propellant burning model that accounts for the effects of time rate of change of the chamber pressure on the burning rate have been used to simulate the internal ballistics of a rocket motor. The compressible convective flow solver used in this study is based on Roe's scheme. The effects of rapid chamber pressure...
Ignition transient simulation in solid propellant rocket motors
, Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 24 , 2007 , Pages 16754-16758 ; 1563478900 (ISBN); 9781563478901 (ISBN) ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2007
Abstract
In this paper, the internal ballistics of a solid propellant rocket motor including a pyrogen type igniter is numerically investigated. The aim of the simulation is to calculate the chamber pressure as a function of time, during flame spreading phase. In addition, effects of the igniter flow on the propellant heat-up and ignition are studied in detail using unsteady quasi one-dimensional conservation equations for a working gas, coupled with the transient conduction within a solid propellant. The convective and radiative heat flux from the igniter flow to the solid surface is considered. The flow-field equations are solved using upwind Roe's scheme. The obtained results can be used to design...
An experimental kinetic optimization of NDMA hydrogenation to UDMH and DMA on a Pd/C catalyst
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Kazememi, M ; Bozorgmehri, R ; Sharif University of Technology
2006
Abstract
The Unsymmetrical dimethyl hydrazine (UDMH) apart from its use as a versatile rocket fuel, finds numerous industrial applications. Interest in UDMH for various applications in the missile and rocket industry has prompted the study of this member of hydrazine family to greater extent. It can be prepared in several ways but one of the most efficient ones which results in higher yields is the catalytic hydrogenation of Nitroso Dimethylamine (NDMA). In this work the kinetic of NDMA to UDMH hydrogenation on a 5% Pd/C in aqueous solution of NDMA was studied experimentally and optimum conditions of the reaction for maximum yield of UDMH in the presence of undesired dimethyl amine (DMA) product was...
Internal ballistics simulation of SRM's: viscous terms effect
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 10 , 2006 , Pages 7669-7672 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Mazaheri, K ; Sharif University of Technology
2006
Abstract
In this paper, the effect of viscosity on internal ballistics simulation of a solid rocket motor with an internal burning cylindrical grain is numerically investigated. Axisymmetric compressible Navier-Stokes equations are discretized by finite volume approach on structured mesh and are solved using upwind Roe's scheme. A quasi steady procedure is used to simulate the regression of the burning surface by using a steady flow solver. Grid resolution is studied to insure acceptable accuracy. It is finally shown that most physical phenomena are quite accurately simulated by using an Euler solver, while NS solvers do not increase the accuracy as much they increase the CPU time
Blast tube effects on internal ballistics of SRM
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 8 , 2006 , Pages 6084-6087 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Ebrahimi, M ; Sharif University of Technology
2006
Abstract
In this paper, the internal ballistics of a solid rocket motor (SRM) including a blast tube is investigated, numerically. Effects of the blast tube presence on the performance of the SRM are studied in detail using unsteady quasi one-dimensional conservation equations. These equations are discretized and solved using upwind Roe's scheme. Any two-dimensional grain configuration can be accounted for if an appropriate geometrical input file is generated using a grain analysis program. The results are presented for several blast tube geometries
Experimental study of fuel regression rate in an HTPB/N2O hybrid rocket motor
, Article Scientia Iranica ; Volume 25, Issue 1 , 2018 , Pages 253-265 ; 10263098 (ISSN) ; Soltani, M. R ; Mohammadi, A. R ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
The performance of an HTPB/N2O hybrid motor was experimentally investigated. A hybrid motor was designed and manufactured in a laboratory with the purpose of studying the effects of various parameters on the motor's performance, including fuel regression rate and specific impulse. A series of tests were conducted to find a correlation between the fuel regression rate and the oxidizer's mass flux. The effects of chamber's pressure on the regression rate as well as other performance parameters were investigated. While the burning rate did not change dramatically, both the efficiency and ISP of the motor increased. The local fuel regression rate and the fuel port were also calculated. In...
A guidance algorithm for launch to equatorial orbit
, Article Aircraft Engineering and Aerospace Technology ; Volume 81, Issue 2 , 2009 , Pages 137-148 ; 00022667 (ISSN) ; Mobed, M ; Sharif University of Technology
2009
Abstract
Purpose - The purpose of this paper is to propose a new guidance algorithm for launching a satellite using an expendable rocket from an equatorial site to an equatorial low-Earth orbit. Design/methodology/approach - Guidance during endoatmospheric portion is based on a nominal trajectory computed prior to take-off. A set of updating computations begins anew at the time instant tg of transition from endoatmosphere to exoatmosphere. The updating computations determine a guidance trajectory and an associated control law for the remainder of path by taking into account the rocket state at time tg. Thus, the overall guidance involves both initial and midcourse operations, and it has both open-...
Thrust termination dynamics of solid propellant rocket motors
, Article Journal of Propulsion and Power ; Volume 23, Issue 5 , 2007 , Pages 1141-1142 ; 07484658 (ISSN) ; Farshchi, M ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2007
Abstract
Thrust termination dynamics of a solid propellant rocket motor that is crucial to the performance of the rocket has been analyzed. Active thrust termination or reversing of a separating motor facilitate the staging process and enhance the performance of a multistage rocket. This can be achieved by opening a secondary nozzle located on the motor head and causing rapid depressurization of the motor chamber. The strong dependence of the solid propellant burning rate on the chamber pressure causes a transient nonlinear behavior that can result in premature dynamic extinguishments of the motor. It was confirmed that there is a maximum achievable level of equilibrium reverse thrust due to...
Non-steady burning effect on solid rocket motor performance
, Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 14 , 2007 , Pages 9531-9536 ; 1563478900 (ISBN); 9781563478901 (ISBN) ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2007
Abstract
Solid rocket performance during rapid pressure excursions differs greatly from predictions based on steady state burning rate data. Rapid pressurization following a chamber filling interval produces indicated burning rate overshoots. Transient internal ballistics of a solid propellant rocket motor during rapid pressurization part of chamber filling phase has been considered in this work. Quasi one-dimensional unsteady Euler equations with a transient propellant burning model that accounts for the effects of time rate of change of the chamber pressure on the burning rate have been used to simulate the internal ballistics of rocket motors. The compressible convective flow solver used in this...
SRM performance improvement: Erosive burning phenomenon
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 10 , 2006 , Pages 7649-7653 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2006
Abstract
In this paper, the internal ballistics of solid propellant rocket motor with an arbitrary grain configuration is numerically investigated using quasi one dimensional simulation of Inviscid conservation equations. The upwind Roe's scheme is used to calculate the convective fluxes. Appropriate burning rate model to predict the erosive burning in solid propellant is used here. By using this phenomenon and accurate simulation, tactical motor performance can be considerably improved
Mode identification of high-amplitude pressure waves in liquid rocket engines
, Article Journal of Sound and Vibration ; Volume 229, Issue 4 , 2000 , Pages 973-991 ; 0022460X (ISSN) ; Mazaheri, K ; Ghafourian, A ; Sharif University of Technology
2000
Abstract
Identification of existing instability modes from experimental pressure measurements of rocket engines is difficult, specially when steep waves are present. Actual pressure waves are often non-linear and include steep shocks followed by gradual expansions. It is generally believed that interaction of these non-linear waves is difficult to analyze. A method of mode identification is introduced. After presumption of constituent modes, they are superposed by using a standard finite difference scheme for solution of the classical wave equation. Waves are numerically produced at each end of the combustion tube with different wavelengths, amplitudes, and phases with respect to each other. Pressure...
Time-varying structural reliability of launch vehicle via extreme response approach
, Article Journal of Spacecraft and Rockets ; Volume 54, Issue 1 , 2017 , Pages 306-314 ; 00224650 (ISSN) ; Pourtakdoust, S. H ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2017
Abstract
Time-varying structural reliability of a multistage solid-propellant launch vehicle subjected to deterministic and stochastic loads is investigated. The study is of practical importance because the launch vehicle's structure is influenced by a combination of external aerodynamics as well as inertial and internal ballistic loads emanating from the solid rocket motors. In addition, as launch-vehicle flight conditions change during flight, the vehicle will be subjected to time-varying loads. In this sense, the environmental, aerodynamic, and internal pressure fluctuations can be interpreted as stochastic forces affecting the launch-vehicle structural reliability. To account for temporal...
rajectory Optimization of the Internally Carried Air Launch
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor) ; Fathi, Mohsen (Supervisor)
Abstract
One of the most interesting and at the same time the newest methods to launch a satellite into space is Air Launch or Launch throw the mother aircraft. The placement of the satellite into space by a rocket in specific altitude and speed is separated from the mother aircraft, takes place. The most problems in multi stage rocket launching is trajectory optimization to reaching the maximum height. The survey was conducted using classical optimization methods, which is derived the equations for the gradient based on the calculus of variations. that can be used or modified for emissions control wings and changing the direction of thrust exhaust. It should be noted that in the model of rigid body...
Integrated Impulsive Maneuver and Propulsion System Design for Upper Stages Guidance of Spacecrafts
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossain (Supervisor)
Abstract
This work is an attempt toward an integrated preliminary design of solid rocket (SR) propulsion system for impulsive orbital maneuvers. In this regard a comparative study is initially performed classifying current space propulsion systems and along the goals of this thesis, solid rocket system was selected for our integrated approach. Subsequently, two integration schemes were studied that differed in the primacy of the two design tasks. This study directed our focus to initially size and design an ideal rocket engine and refine it through integration with the maneuver design. Utilizing the ideal rocket concept and its governing equations, a SR was designed to provide the required total...
Analytical Solution of the Swirl Flow in Combustion Chamber of a Hybrid Rocket Engine
, M.Sc. Thesis Sharif University of Technology ; Farahani, Mohammad (Supervisor) ; Rezayi, Hadi ($item.subfieldsMap.e)
Abstract
Hybrid engines are one of a variety of chemical propulsion systems that have been given special attention in recent years by various industries such as space and defense. The most important reasons for considering this type of system are its high safety, its affordable price compared with liquid fuel propulsion systems, the possibility of switching on and off and changing thrust. This system has a lot of disadvantages as well. This system cannot meet all the needs of different industries due to the low regression rate and, consequently, the limitation of the operating range, thrusts and special impulse. As a result, increasing the fuel regression rate in these engines can greatly expand...
Swirl effects on spinning solid propellant rocket motor performance
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 6 , 2006 , Pages 4586-4590 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Mazaheri, K ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2006
Abstract
Spining is used in some of solid rocket motors to increase the flight trajectory precision or for stability requirements. The angular acceleration due to the spin increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. On the other hand, due to the rocket and its grain rotation, the gases injected from propellant surface to the flow field have an initial angular velocity. The angular velocity of each particle increases as it approaches to the center due to the conservation of angular momentum and a reduction in its radial location, although it vanishes close to the central axis due to viscous...
Increasing isp by injecting water into combustion chamber of an underwater SRM
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 8 , 2006 , Pages 6088-6093 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Ebrahimi, M ; Sharif University of Technology
2006
Abstract
In this paper, the effects of water addition to a solid rocket motor (SRM) with an end-burning grain configuration are investigated, numerically. Inviscid quasi one-dimensional conservation equations are discretisked and solved using upwind Roe's scheme together with appropriate boundary conditions. The set of assumptions made to solve the problem are described in detail and the results are presented for several water inlet diameters and pressures. It is shown that, the penetration of a certain volume of water into combustion chamber can result in an ISP increase of up to 14% and therefore a performance enhancement with no extra mass of propellant