Interaction of Liquid Propellant and Coupled System Structure for Atlas V Launch Vehicle

2010 ◽  
Author(s):  
Kirk W. Dotson ◽  
Brian H. Sako ◽  
Daniel R. Morgenthaler
Keyword(s):  
Hydraulic System ◽  
Coupled System ◽  
Launch Vehicle ◽  
System Structure ◽  
Liquid Oxygen ◽  
Launch Vehicles ◽  
Liquid Propellant ◽  
Pressure Oscillations ◽  
Maximum Acceleration ◽  
Structure Interaction

In structural modeling of launch vehicles, liquid propellant is sometimes rigidly attached to feedline walls. This assumption precludes the interaction of structural modes with propellant pressure and flow. An analysis of fluid-structure interaction (FSI) for the Atlas V launch vehicle revealed that structural models with rigidly-attached propellant yield unconservative response predictions under some conditions. In particular, during the maximum acceleration time of flight, pressure oscillations acting at bends in the Atlas V liquid oxygen (LO2) feedline excite 15–20 Hz structural modes that have considerable gain on the feedline and at the spacecraft interface. The investigation also revealed that the venting of gas from the pogo accumulator is an excitation source and changes the dynamic characteristics of the hydraulic system. The FSI simulation produced during the investigation can be adapted to mission-specific conditions, such that responses and loads are conservatively predicted for any Atlas V flight.

Thermal-Fluidic Numerical Analysis for the Development of Heat Exchanger in the Propellant Tank Pressurization System of KSLV-II Upper Stage

2015 ◽  
Author(s):  
Sun-Kyung Lee ◽  
Sang Yeop Han ◽  
Dong-Soon Shin ◽  
R. Ray Taghavi
Keyword(s):  
Heat Exchanger ◽  
Numerical Analysis ◽  
Coming Out ◽  
Launch Vehicle ◽  
Liquid Oxygen ◽  
Outlet Temperature ◽  
Liquid Propellant ◽  
Gaseous State ◽  
Technical Requirements ◽  
Upper Stage

KSLV-II (Korea Space Launch Vehicle - II) launch vehicle is a three staged satellite launch vehicle using a liquid propellant propulsion system in all three stages. It will deliver 1,500 kg satellite to Sun Synchronous Orbit (SSO, 700 km, 98.2°) or 2,600 kg satellite to Low Earth Orbit (LEO, 300 km, 80.3°). Propellants for KSLV-II are kerosene as a fuel and liquid oxygen as an oxidizer for propelling. Those fuel and oxidizer are stored in on-board tanks separately. To run a liquid propellant rocket engine on ground or in flight, those propellants should be supplied to LRE’s using so-called Propellant Pressurizing Sub-system, which makes propellants be pressurized in tanks using pressurant. A pressurant for PPSS of KSLV-II is helium, which is stored in tanks located in an oxidizer tank. The stored He is under cryogenic condition (50 K) as gaseous state. Such He is heated and expanded through heat exchanger, which is using a combustion gas coming out from gas generator for turbo-pump as an energy source, to be used as pressurant. This paper contains the results of performance analysis and thermal-fluidic numerical analysis to develop the above-mentioned heat exchanger for KSLV-II upper stage (the 2nd stage). The technical requirements for such heat exchanger are as follows: pressurant mass flow rate for oxidizer tank - 0.127 kg/sec; and for fuel tank - 0.043 kg/sec. The outlet temperature of He from heat exchanger is 550±10 K.

Fluid Mode Excitation in Launch Vehicle Feed Lines Induced by Pogo Accumulator Venting

2014 ◽  
Author(s):  
Kirk W. Dotson ◽  
Brian H. Sako ◽  
Trinh T. Nguyen
Keyword(s):  
Space Vehicle ◽  
Launch Vehicle ◽  
Liquid Oxygen ◽  
Rocket Engines ◽  
Launch Vehicles ◽  
Feed Line ◽  
Large Pressure ◽  
Structural Responses ◽  
Flow Oscillations ◽  
Liquid Rocket

Launch vehicles with liquid rocket engines have feed lines through which propellants flow to the engine. To prevent feedback between structural responses and propellant pressure and flow oscillations, a compliant device called a pogo accumulator is typically installed in the propellant feed line. Even if a catastrophic interaction is thus averted, the fluid-induced structural responses may exceed those for important flight events such as liftoff and atmospheric buffeting. In that case, the fluid-induced excitation must be predicted in order to ensure adequate structural margins for the launch vehicle and space vehicle hardware. Venting of compliant gas in the pogo accumulator prior to engine shutdown is known to exacerbate the fluid-induced excitation. In particular, for the Atlas V launch vehicle, a 5–7 Hz fluid mode with large pressure gains at the aft end of the liquid oxygen feed line often excites structural modes just prior to engine cutoff. A methodology for the prediction of these structural responses is presented.

scholarly journals Experimental and Computational Modal Analyses for Launch Vehicle Models considering Liquid Propellant and Flange Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Chang-Hoon Sim ◽  
Geun-Sang Kim ◽  
Dong-Goen Kim ◽  
In-Gul Kim ◽  
Soon-Hong Park ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Natural Frequencies ◽  
Launch Vehicle ◽  
Mode Shapes ◽  
Launch Vehicles ◽  
Liquid Propellant ◽  
Element Modeling ◽  
Space Launch ◽  
Modeling Techniques

In this research, modal tests and analyses are performed for a simplified and scaled first-stage model of a space launch vehicle using liquid propellant. This study aims to establish finite element modeling techniques for computational modal analyses by considering the liquid propellant and flange joints of launch vehicles. The modal tests measure the natural frequencies and mode shapes in the first and second lateral bending modes. As the liquid filling ratio increases, the measured frequencies decrease. In addition, as the number of flange joints increases, the measured natural frequencies increase. Computational modal analyses using the finite element method are conducted. The liquid is modeled by the virtual mass method, and the flange joints are modeled using one-dimensional spring elements along with the node-to-node connection. Comparison of the modal test results and predicted natural frequencies shows good or moderate agreement. The correlation between the modal tests and analyses establishes finite element modeling techniques for modeling the liquid propellant and flange joints of space launch vehicles.

scholarly journals Development of Solid Gas Generating Compositions to Ensure Non Explosiveness of Spent Orbital Stages of Liquid Rocket of Space Launch Vehicles

2017 ◽  
Vol 19 (1) ◽  
pp. 63
Author(s):  
V. Trushlyakov ◽  
K. Zharikov ◽  
D. Lempert
Keyword(s):  
Rocket Engine ◽  
Drainage System ◽  
Combustion Products ◽  
Launch Vehicle ◽  
Liquid Oxygen ◽  
Launch Vehicles ◽  
Gas Generator ◽  
Space Launch ◽  
Surrounding Space ◽  
Liquid Rocket

The choice is discussed of solid gas generating compositions for venting by hot combustion products a fuel tank of the spent orbital stage of a space launch vehicle with a main liquid rocket engine. Non explosiveness is achieved via eliminating the<br />possibility of freezing the drainage system when products of gasification (vapours of a propellant component + the remains of a gas boost + the hot products of combustion of solid gas generating compositions) are discharged from the tank into surrounding space. There are imposed requirements, constraints, and criteria for selecting solid gas generating compositions. When considering tank with the residues of liquid oxygen belonging to orbital spent stage of the launch vehicle «Zenith» the ways are shown how to ensure explosion safety, which on the basis of proposed approaches by selecting solid gas generating compositions (SGC) which generate oxygen and<br />nitrogen. As a criterion of choice of SGC the total mass of the gasification system is adopted, which includes the SGC mass for gasification of liquid propellant residues, the mass of the gas generator and the mass of system to supply the combustion products of SGC into the tank. It is proposed use of residual heat in the condensed phase of the SGC combustion products to heat up the drainage system, which will increase the probability of a trouble-free operation of the drainage system.

Theoretical evaluation of the amplitudes of pogo vibrations in liquid propellant launch vehicles

1999 ◽  
Vol 5 (1) ◽  
pp. 90-96 ◽  
Author(s):  
V.V. Pilipenko ◽  
◽  
N.I. Dovgot'ko ◽  
S.I. Dolgopolov ◽  
A.D. Nikolaev ◽  
...  
Keyword(s):  
Launch Vehicles ◽  
Liquid Propellant ◽  
Theoretical Evaluation

Thermo-structural analysis of cryogenic tanks with common bulkhead configuration

2021 ◽  
pp. 095441002110247
Author(s):  
S Sumith ◽  
R Ramesh Kumar
Keyword(s):  
Structural Analysis ◽  
Temperature Gradient ◽  
Thermal Gradient ◽  
Load Transfer ◽  
Thermal Analyses ◽  
Positive Margin ◽  
Heat Transfer Analysis ◽  
Liquid Oxygen ◽  
Launch Vehicles ◽  
Element Analysis

In launch vehicles, cryogenic propulsion stages store liquid oxygen (LOX) at 76 K and liquid hydrogen (LH2) at 20 K, generally in two separate insulated tanks connected through tubular truss components. Consequently, load transfer from the LH2 tank to the LOX tank is very much localized, resulting in a nonoptimal design. This article presents an alternative single tankage design using a common bulkhead (CBH) to enhance the payload capability, which enables maintaining LH2 temperature within a specified temperature when exposed to a temperature gradient. A sandwich insulator using aramid honeycomb embedded with polyimide foam keeps the LH2 temperature within 20 ± 1 K is proposed, based on transient heat transfer analysis for 1000 s. The foam-filled honeycomb core is treated as equivalent foam in the analysis as the thermal conductivity of the core and the foam is quite close. The efficacy of the insulator is established by an experiment to measure the back wall temperature when liquid nitrogen is loaded on the top skin of the panel, and the insulator maintains a temperature gradient of 123 K for 1000 s. A good agreement is obtained between the transient finite element analysis results with experimental data. An externally insulated LOX tank configuration with an optimum length of the skirt–cylinder where the temperature reaches 80 K is arrived at based on slosh, buckling, and thermal analyses. No thermal gradient is found across the thickness of the skirt, while the thermal gradient is observed along the length of the skirt as anticipated. An integrated thermo-structural analysis of the cryo-system is carried out considering temperature-dependent material properties. A positive margin for the skirt is obtained. A payload gain of 366 kg is estimated based on the present study for the new design option with a CBH and skirt as compared to the traditional tubular truss arrangements.

A numerical study on the influences of underlying soil and backfill characteristics on the dynamic behaviour of typical integral bridges

Bauingenieur ◽  
2020 ◽  
Vol 95 (11) ◽  
pp. S 2-S 11
Author(s):  
H. D. B. Aji ◽  
M. B. Basnet ◽  
Frank Wuttke
Keyword(s):  
Soil Structure ◽  
Dynamic Behaviour ◽  
Numerical Study ◽  
Coupled System ◽  
Soil Structure Interaction ◽  
Dynamic Resistance ◽  
Soil Characteristic ◽  
Structure Interaction ◽  
Integral Bridges ◽  
Underlying Soil

Abstract The identification of the dynamic behaviour of a structure is one of the crucial steps in the design of the dynamic resistance of the structure. The dynamic behaviour is represented by the natural frequencies and damping which are subsequently used along with the considered dynamic actions in the design process. In regard of integral bridge concept, one of the consequences of the omission of joints and bearings is the substantial soil-structure interaction which in turn increases the sensitivity of the dynamic behaviour of the bridges to the surrounding soil characteristic. In this article, we extended our hybrid BEM-FEM steady-state dynamic numerical tool to the 3D regime, developed by utilizing an in-house BEM and the commercial FEM software ABAQUS and use it to analyse the dynamic interaction between the bridge and the underlying soil as well as the backfill. The numerical results from four typical integral bridges show that underlying soil characteristic has great effect on the resonant frequencies and the damping. The backfill material properties tend to have less significant role due to the abutment wingwalls dominating the force transfer between the soil and the superstructure. The results also show that the degree of influence of the soil-structure interaction on the coupled system is affected by the type of load pattern in addition to the flexural stiffness of the superstructure.

scholarly journals Design and simulation of hydraulic system for launch vehicle holding device

2016 ◽  
Vol 44 (12) ◽  
pp. 1087-1094 ◽  
Author(s):  
Dae Rae Kim ◽  
Seong Pil Yang ◽  
Jaejun Lee ◽  
Bum Suk Kim ◽  
Young-Shin Lee
Keyword(s):  
Hydraulic System ◽  
Launch Vehicle ◽  
Holding Device

Scalability study of an implicit solver for coupled fluid-structure interaction problems on unstructured meshes in 3D

2016 ◽  
Vol 32 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Fande Kong ◽  
Xiao-Chuan Cai
Keyword(s):  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Coupled System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Krylov Method ◽  
Fine Mesh ◽  
Processor Cores ◽  
Fully Coupled

Fluid-structure interaction (FSI) problems are computationally very challenging. In this paper we consider the monolithic approach for solving the fully coupled FSI problem. Most existing techniques, such as multigrid methods, do not work well for the coupled system since the system consists of elliptic, parabolic and hyperbolic components all together. Other approaches based on direct solvers do not scale to large numbers of processors. In this paper, we introduce a multilevel unstructured mesh Schwarz preconditioned Newton–Krylov method for the implicitly discretized, fully coupled system of partial differential equations consisting of incompressible Navier–Stokes equations for the fluid flows and the linear elasticity equation for the structure. Several meshes are required to make the solution algorithm scalable. This includes a fine mesh to guarantee the solution accuracy, and a few isogeometric coarse meshes to speed up the convergence. Special attention is paid when constructing and partitioning the preconditioning meshes so that the communication cost is minimized when the number of processor cores is large. We show numerically that the proposed algorithm is highly scalable in terms of the number of iterations and the total compute time on a supercomputer with more than 10,000 processor cores for monolithically coupled three-dimensional FSI problems with hundreds of millions of unknowns.

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