Download or read book Simulation of Bulk Evaporation and Condensation in Cryogenic Propellant Tanks Using the Energy of Fluid Method written by Elijah Gasmen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of cryogenic propellant storage systems for long duration space missions relies on accurate prediction of tank self-pressurization. Incident solar radiation heats the cryogenic liquids in the tank over time, vaporizing the cryogenic liquid. As the liquid vaporizes, the tank pressure increases. The objective of the current research is to develop a finite volume based Compuational Fluid Dynamic (CFD) model of tank pressurization in reduced gravity using an Energy of Fluid (EOF) method. A commercially available CFD model is significantly enhanced to include the EOF method, which will solve the energy equation in terms of internal energy. Model validation results are presented which include a comparison of temperature and pressure predictions to the data collected during the terrestrial experiments performed by Aydelott and the low gravity experiment conducted onboard the Saturn IB AS203 tank.

Download or read book Modeling of Bulk Evaporation and Condensation written by and published by . This book was released on 1996 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Cryogenic Propellant Tank Pressurization based upon Experiments and Numerical Simulations written by Carina Ludwig and published by Cuvillier Verlag. This book was released on 2014-09-04 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focus of this study is the pressurization system of a cryogenic liquid propellant tank for the launcher application. Objective of the pressurization system is to provide the required pressure evolution in the propellant tank for a proper operation of the engine. The motivation of this study is an improved understanding of the complex fluid-dynamic and thermodynamic phenomena during the active-pressurization process of cryogenic propellants in order to optimize the on-board pressurant gas mass. Therefore ground experiments, numerical simulations and analytical considerations were performed for the investigation of the initial active-pressurization phase. For the performed experiments, liquid nitrogen was used as cryogenic model propellant, which was actively pressurized under normal gravity conditions up to different final tank pressures. As pressurant gases, gaseous nitrogen and gaseous helium were used with different inlet temperatures. For the numerical analyses the commercial CFD program Flow-3D, a three-dimensional Navier-Stokes equation solver, was used.

Download or read book Numerical Modelling of Heat Transfer and Evaporation Characteristics of Cryogenic Liquid Propellant written by Arun Tamilarasan and published by . This book was released on 2015 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive and active technologies have been used to control propellant boil-off, but the current state of understanding of cryogenic evaporation and condensation in microgravity is insufficient for designing large cryogenic depots critical to the long-term space exploration missions. One of the key factors limiting the ability to design such systems is the uncertainty in the accommodation coefficients (evaporation and condensation), which are inputs for kinetic modeling of phase change. A novel, combined experimental and computational approach is being used to determine the accommodation coefficients for liquid hydrogen. The experimental effort utilizes the Neutron Imaging Facility located at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to image evaporation and condensation of propellants inside of metallic containers. CFD tools are utilized to infer the temperature distribution in the system and determine the appropriate thermal boundary conditions for the numerical solution of the evaporating and condensing liquid to be used in a kinetic phase change model. Using all three methods, there is the possibility of extracting the accommodation coefficients from the experimental observations.

Download or read book Non equilibrium Evaporation and Condensation Processes written by Yuri B. Zudin and published by Springer. This book was released on 2017-09-14 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents a comprehensive treatment of analytical solutions to problems in the area of non-equilibrium evaporation and condensation processes. The book covers, among others, topics such as systems of conversation equations for molecular fluxes of mass, momentum and energy within the Knudsen layer, spherical growth of vapor bubbles in volumes of highly superheated liquid. The target audience primarily comprises research experts in the field of thermodynamics and fluid dynamics, but the book may also be beneficial for graduate students alike.

Download or read book Effect of Roughness Elements on the Evolution of Thermal Stratification in a Cryogenic Propellant Tank written by S.B. Vishnu and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cryogenic propulsion era started with the use of liquid rockets. These rocket engines use propellants in liquid form with reasonably high density, allowing reduced tank size with a high mass ratio. Cryogenic engines are designed for liquid fuels that have to be held in liquid form at cryogenic temperature and gas at normal temperatures. Since propellants are stored at their boiling temperature or subcooled condition, minimal heat infiltration itself causes thermal stratification and self-pressurization. Due to stratification, the state of propellant inside the tank varies, and it is essential to keep the propellant properties in a predefined state for restarting the cryogenic engine after the coast phase. The propellant,Äôs condition at the inlet of the propellant feed system or turbo pump must fall within a narrow range. If the inlet temperature is above the cavitation value, cavitation will likely to happen to result in the probable destruction of the flight vehicle. The present work aims to find an effective method to reduce the stratification phenomenon in a cryogenic storage tank. From previous studies, it is observed that the shape of the inner wall surface of the storage tank plays an essential role in the development of the stratified layer. A CFD model is established to predict the rate of self-pressurization in a liquid hydrogen container. The Volume of Fluid (VOF) method is used to predict the liquid,Äìvapor interface movement, and the Lee phase change model is adopted for evaporation and condensation calculations. A detailed study has been conducted on a cylindrical storage tank with an iso grid and rib structure. The development of the stratified layer in the presence of iso grid and ribs are entirely different. The buoyancy-driven free convection flow over iso grid structure result in velocity and temperature profile that differs significantly from a smooth wall case. The thermal boundary layer was always more significant for iso grid type obstruction, and these obstructions induces streamline deflection and recirculation zones, which enhances heat transfer to bulk liquid. A larger self-pressurization rate is observed for tanks with an iso grid structure. The presence of ribs results in the reduction of upward buoyancy flow near the tank surface, whereas streamline deflection and recirculation zones were also perceptible. As the number of ribs increases, it nullifies the effect of the formation of recirculation zones. Finally, a maximum reduction of 32.89% in the self-pressurization rate is achieved with the incorporation of the rib structure in the tank wall.

Download or read book Initial Investigation of a Method Whereby a Cryogenic Propellant Liquid is Insulated from Heat Leak by the Propellant and Its Sacrificial Boiloff written by William A. Olsen and published by . This book was released on 1966 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of cryogenic sloshing including heat and mass transfer written by Arnold van Foreest and published by Cuvillier Verlag. This book was released on 2014-03-10 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sloshing of cryogenic liquid propellants in launch vehicle tanks creates unwanted thermodynamic side-effects such as pressure changes in the tank. The goal of this PhD research was to develop a practical engineering model which is able to describe the influence of the sloshing of a cryogenic liquid on the heat and mass transfer and the associated temperature and pressure. The pressure changes caused by sloshing were investigated experimentally and numerically. Using the experimental and numerical results, a one dimensional (1D) engineering model was developed which is able to describe the experimental results.

Download or read book Capillary transport of cryogenic liquids in porous structures written by Ming Zhang and published by Cuvillier Verlag. This book was released on 2013-06-18 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: In space, liquids behave differently than on earth due to lack of gravity. For gas-free propellant delivery a Propellant Management Device (PMD) or Liquid Acquisition Device (LAD) is often applied in space technology. Its proper functioning is ensured by employing porous structures due to the wicking effect (capillarity). A better understanding of wicking process with cryogenic liquids is essential for the design of future PMDs, which employ cryogenic propellants. The first part of this work focuses on the mathematical modelling and experimental investigation of wicking processes with liquid nitrogen. The influence of liquid evaporation on wicking processes can be described by newly derived mathematical equations, which have a similar form to the Lucas-Washburn equation. The second part of this work deals with CFD simulations of wicking processes on both microscopic and macroscopic scales. Simulations on the microscopic scale aim to achieve structure parameters of the investigated porous media such as permeability, static pore radius and porosity. The surface geometries of the porous media are obtained through CAD program or computer tomography (CT). Simulations on the macroscopic scale treat porous structures as a macroscopic continuum, which is then described with previously obtained structure parameters.

Download or read book Principles of Design of Dynamically Similar Models for Large Propellant Tanks written by Paul Edwin Sandorff and published by . This book was released on 1960 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Technique to Determine Accommodation Coefficients of Cryogenic Propellants written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : The control of propellant boil-off is essential in long-term space missions. However, a clear understanding of cryogenic propellant phase change and the values of accommodation coefficients are lacking. To that effect, a new method to determine accommodation coefficients using a combination of neutron imaging, thin film evaporation modeling and CFD modeling has been established. Phase change experiments were conducted in the BT-2 Neutron Imaging Facility at the National Institute of Standards and Technology (NIST) by introducing cryogenic vapor (H2 and CH4) at a set pressure into Al6061 and SS316L test cells placed inside a 70mm cryostat. Condensation is achieved by lowering the cryostat temperature below the saturation condition and vice versa for evaporation. Neutron imaging is used to visualize the liquid-vapor interface inside metallic containers due to the difference in attenuation between the cryogen and the metal. Phase change tests are conducted using liquid hydrogen and methane at a range of saturation points between 80 - 230 kPa and corresponding phase change rates were determined. The contact resistances and other transient heat transfer properties of the cryostat setup is determined from the combination of a CFD thermal transport model and a "dry" thermal cycling test. The calibrated CFD model then allows for the determination of the inner wall temperature profile. Results from neutron imaging and the thermal model serve as boundary conditions to a multiscale evaporation model. A macroscale 2D FEA model is used to compute evaporation flux in the bulk meniscus while a thin film evaporation model is used to account for enhanced evaporation near the contact line. Using a combination of neutron imaging, CFD thermal model and a multiscale evaporation model, there is a possibility to extract the accommodation coefficient while accounting for the curvature, disjoining pressure and a variable interface temperature. The accommodation coefficient of H2 decreases from 0.65±0.12 at 88 kPa to 0.22±0.1 at 226 kPa and is independent of container material/geometry. The error is dominated by the uncertainty in the temperature measurements (±0.25K)

Download or read book Experimental Investigation of Glass Flakes as a Liner for Fiber glass Cryogenic Propellant Tanks written by Robert W. Frischmuth (Jr.) and published by . This book was released on 1966 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Principles of Design of Dynamically Similar Models for Large Propellant Tanks written by Paul E. Sandorff and published by . This book was released on 1960 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulator for Static Liquid Configuration in Propellant Tanks Subject to Reduced Gravity written by William A. Olsen and published by . This book was released on 1966 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermomechanical Simulation of an Aerogel RTV 655 Based Cryogenic Propellant Tank written by William Dalton Bowen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing an effective solution for long duration storage of cryogenic liquids is crucial for future, manned space exploration missions. Current storage tanks are made of metals or composites. Although these materials have a relatively high mechanical strength, their high thermal conductivity is a disadvantage with regards to heat infiltration. The influx of heat causes vaporization, increasing the pressure in the tank. To reduce tank pressurization rates, novel materials with densities and thermal conductivities which are lower than metals, such as RTV-655 and aerogels, have been developed which may be feasible for space applications. Due to the complexity and costs of performing experiments, a thermomechanical computational model is desired to further study the feasibility of using these novel materials. A thermomechanical finite element simulation is used to simulate the Cooldown and Pressurization phases of RTV-655 and RTV-655/Aerogel tank experiments and a comparison of the simulation and experimental results are presented.

Download or read book Comparison of Propellant Sloshing Parameters Obtained from Model and Full size Centaur Liquid oxygen Tanks written by Andrew J. Stofan and published by . This book was released on 1966 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Modeling of a Cryogenic Fluid Within a Fuel Tank written by Donald S. Greer and published by . This book was released on 1994 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The computational method developed to study the cryogenic fluid characteristics inside a fuel tank in a hypersonic aircraft is presented. The model simulates a rapid draining of the tank by modeling the ullage vapor and the cryogenic liquid with a moving interface. A mathematical transformation was developed and applied to the Navier-Stokes equations to account for the moving interface. The formulation of the numerical method is a transcient hybrid explicit-implicit technique where the pressure term in the momentum equations is approximated to first order in time by combining the continuity equation with an ideal equation of state.