Modeling and Analysis of Cryogenic Pressure vessel using FEA

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1 Modeling and Analysis of Cryogenic Pressure vessel using FEA E. Lakshmi Devi #1, V. Hari Shankar *2 # M. Tech, Department of Mechanical Engg. Visakha Technical Campus, Narava Visakhapatnam, Andhra Pradesh, India Abstract In the present work, design analysis of multi layered cryogenic shell, with optimum orientations; minimum mass under strength constraints for a cylinder subjected to axial loading for static analysis on the pressure vessel has been studied. The modeling is carried out in Creo Parametric 2.0 and the analysis is carried out in Ansys 15.0 solver. Static load analysis and Thermal analysis is done and also material optimisation is done for enhancement. Different materials are analysed. Taking weight into consideration and stress into account, S- glass epoxy for the outer structure with aluminium for the inner structure is comparably better than the other materials. Keywords Cryogenic, high pressure, insulated chambers, Stiffening rings. I. INTRODUCTION The denotation cryogenics is defined as the study of a liquefied gas at very low temperature (below 150 C), as well as how materials perform at the aforementioned temperature. At cryogenic temperature all gases are in liquefied form. For example at -162 c temp. Methane is in liquefied form and it has 580 times less volume then it is at room temperature. So it is possible to transport large quantity of methane in small tank. At current scenario size of Industries are becoming smaller. Medium sized and contract base industries are developing very rapidly. This kind of industries requires medium sized cryogenic tank which can transport 1000 to 4000 liters of cryogenic liquids. Current requirement of industries is a tank which can transport required quantity of cryogenic liquids and which can be also works dually as transportable or stationary storage. A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure. Pressure vessels are used in a variety of applications in both industry and the private sector. They appear in these sectors as industrial compressed air receivers and domestic hot water storage tanks. Other examples of pressure vessels are diving cylinders, recompression chambers, distillation towers, pressure reactors, autoclaves, and many other vessels in mining operations, oil refineries and petrochemical plants, nuclear reactor vessels, submarine and space ship habitats, pneumatic reservoirs, hydraulic reservoirs under pressure, rail vehicle airbrake reservoirs, road vehicle airbrake reservoirs, and storage vessels for liquefied gases such as ammonia, chlorine, propane, butane, and LPG. II. PRESSURE TEST A. Pressure Test and Cryogenic Temperature Shock Conditioning: The aramid-aluminium pressure vessel insulated with MLVSI will be pressure tested and shock-conditioned. Pressure and shock test will be done in preparation for liquid hydrogen fill tests, described in the next section. The vessel will be equipped with temperature, pressure and level sensors, necessary for determining the amount of fluid contained in the vessel. The experimental setup for this test is the same as previously used for cyclic testing. The test procedure will be as follows: The vessel will be pressurized with compressed helium to 1.2 times the Maximum Allowable Working Pressure (MAWP). The pressure will be held for a minimum of 30 minutes. Then, the pressure vessel will be shock conditioned by cycling it 3 times to low temperature with liquid nitrogen. Finally, the vessel will be leak tested with helium to 0.25 times the MAWP. Any leakage detected with a mass spectrometer leak detector is unacceptable. B. Testing of a Pressure Vessel with Liquid and Gaseous Hydrogen: The shock tested insulated pressure vessels will be transported to a remote facility for testing with liquid and gaseous hydrogen. Testing will involve filling the vessel with LH2 to study the insulation performance, the accuracy of the sensors, and the problems involved with pumping the LH into the vessel. The vessel will also be pressurized with compressed hydrogen to the working pressure. This test is expected to replicate what would happen to the vessel during fueling and operation in an LHIfueled car. III. LITERATURE REVIEW Journal papers and patents explored here are related directly or indirectly to the proposed area of work that is design and development of a Cryogenic vessel. These papers are to support and enlighten the whole process of design in the specific area. ISSN: Page 261

2 E. Lisowski [1] in his paper stated that the present study was intended to develop a concept for a Cryogenic vessel, with the motivation of Technical gases becomes liquid in extremely low temperature ranging minus 200 C and very high pressure what makes that transportation devices have to perform very strict requirement. Presented paper shows selected aspect of simulation of liquefied gas sloshing in aspect of requirements that mobile vessels have to fulfil. Mobile vessel which is the object of simulation is a two shell tank with vacuum and layer insulation between shells adapted to 20 ft container. It is assigned for see, railway and road transport and have to follow all of requirements for such transportation systems. Requirements for such tank are enclosed in standard ISO which deals with freight containers and standard EN that describes vacuum, cryogenic vessels. The standards EN defines that vessels which are to be filled equal or less than 80% should be fitted with surge plates to provide vessel stability and limit dynamic loads. Additionally surge plates area has to be at least 70% of cross section of the vessel and volume between surge plates shall be not higher than 7.5 m3. Structure of the vessel as well as the surge plate should resist of longitudinal acceleration of 2g. Additionally surge plates shall resists stresses caused by pressure distributed across the area of surge plate and the pressure shall be calculated as mass of liquid between plates and acceleration 2g. In this paper is presented way of simulation of dynamic behaviour of liquefied Argon on vessel structure. A numerical methods like Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) were used for this purpose. Combination of both tools allowed to get pick value of dynamic pressure that arising during acceleration of 2g, which was assumed is 0.2 s and investigate resistance of vessel and container structure. Presented approach is called Fluid Structure Interaction simulation. In CFD simulation was used Ansys CFX code, while for FEA calculations Pro/Mechanica package. K. J. Jaya Kumar, [2] in his paper discussed that the application of lightweight materials in spherical tank designs for cryogenic tanks. Two cryogenic hydrogen tank design concepts will be considered. This paper is prepared with MatLab and Abacus Version and the Analysis will include thermal and structural analysis of the tank designs as well as an analysis of hydrogen diffusion to specify the material permeability requirements. Thermal modeling and analysis of a cryogenic tank design exposed to extreme heating profiles, Thermal performance comparison of insulation systems for liquid hydrogen storage tanks, Analysis of cryogenic propellant tank pressurization based upon ground experiments. A vacuum-jacketed design with an aluminum tank offered the most efficient thermal insulation design option. A tank design with high or low density aerogels results in a much heavier tank system, due to a higher rate of heat penetration and more propellant boil off. As such, aerogels are not a viable insulation option for the storage of cryogenic fuels. SM. Aceves, [3] in his paper described that an analytical and experimental evaluation of the applicability of insulated pressure vessels for hydrogen-fuelled light-duty vehicles. Insulated pressure vessels are cryogenic-capable pressure vessels that can be fuelled with liquid hydrogen (LH?) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The purpose of this work is to verify that commercially available aluminum-lined, fiber wrapped vessels can be used for cryogenic hydrogen storage. The paper reports on previous and ongoing tests and analyses that have the purpose of improving the system design and assure its safety. The analytical and experimental results carried out until now indicate that it may be possible to use fiber-wrapped aluminum-lined vessels for operation at LH2 temperature and high pressure. Required future tests are described that will assure vessel safety under daily operating conditions. Craig A. Stephens[4] in his study stated that cryogenic test article, the Generic Research Cryogenic Tank, was designed to qualitatively simulate the thermal response of trans-atmospheric vehicle fuel tanks exposed to the environment of hypersonic flight. One-dimensional and twodimensional finite-difference thermal models were developed to simulate the thermal response and assist in the design of the Generic Research Cryogenic Tank. The one dimensional thermal analysis determined the required insulation thickness to meet the thermal design criteria and located the purge jacket to eliminate the liquefaction of air. The twodimensional thermal analysis predicted the temperature gradients developed within the pressurevessel wall, estimated the cryogen boil off, and showed the effects the ullage condition has on pressure-vessel temperatures. The degree of ullage mixing, location of the applied high-temperature profile, and the purge gas influence on insulation thermal conductivity had significant effects on the thermal behaviour of the Generic Research Cryogenic Tank. IV. MODELING OF CRYOGENIC VESSEL Creo Parametric is a computer graphics system for modeling various mechanical designs and for performing related design and manufacturing operations. The system uses a 3D solid modeling system as the core, and applies the feature-based, ISSN: Page 262

3 parametric modeling method. In short, Creo Parametric is a feature-based, parametric solid modeling system with many extended design and manufacturing applications. Creo Parametric is the first commercial CAD system entirely based upon the feature-based design and parametric modeling philosophy. Today many software producers have recognized the advantage of this approach and started to shift their product onto this platform. Nevertheless, the differences between a feature-based, parametric solid modeling CAD system, such as Creo Parametric, and a conventional CAD system include: Creo Parametric Conventional CAD Systems Solid Model Wireframe and Solid Model Parametric Model Fixed-dimension Model Feature-based Modeling Primitive-based Modeling A Single Data Structure and Full Function- Oriented Data Structures Associativity with Format Interpreters Subject-oriented Sub-modeling Systems A Single Geometry-Based System Manufacturing Information Texts Attached to Geometry Entities Associated with Features Generation of an Assembly by Generation of an Assembly by Assembling Components Positioning Components. The modeling is done in Creo Parametric 2.0. and the model is as shown in the Fig.1 Fig. 1 Cryogenic vessel model The finite element method is numerical analysis technique for obtaining approximate solutions to a wide variety of engineering problems. Because of its diversity and flexibility as an analysis tool, it is receiving much attention in engineering schools and industries. In more and more engineering situations today, we find that it is necessary to obtain approximate solutions to problems rather than exact closed form solution. It is not possible to obtain analytical mathematical solutions for many engineering problems. An analytical solutions is a mathematical expression that gives the values of the desired unknown quantity at any location in the body, as consequence it is valid for infinite number of location in the body. For problems involving complex material properties and boundary conditions, the engineer resorts to numerical methods that provide approximate, but acceptable solutions. The finite element method has become a powerful tool for the numerical solutions of a wide range of engineering problems. It has developed simultaneously with the increasing use of the highspeed electronic digital computers and with the growing emphasis on numerical methods for engineering analysis. This method started as a generalization of the structural idea to some problems of elastic continuum problem, started in terms of different equations or as an extremum problem. The fundamental areas that have to be learned for working capability of finite element method include: Matrix algebra. Solid mechanics. Variational methods. Computer skills. Matrix techniques are definitely most efficient and systematic way to handle algebra of finite element method. Basically matrix algebra provides a scheme by which a large number of equations can be stored and manipulated. Since vast majority of literature on the finite element method treats problems in structural and continuum mechanics, including soil and rock mechanics, the knowledge of these fields became necessary. It is useful to consider the finite element procedure basically as a Variational approach. This conception has contributed significantly to the convenience of formulating the method and to its generality. The term finite element distinguishes the technique from the use of infinitesimal differential elements used in calculus, differential equations. The method is also distinguished from finite difference equations, for which although the steps in to which space is divided into finite elements are finite in size; there is a little freedom in the shapes that the discrete steps can take. F.E.A is a way to deal with structures that are more complex than dealt with analytically using the partial differential equations. F.E.A deals with complex boundaries better than finite difference equations and gives answers to the real world structural problems. It has been substantially extended scope during the roughly forty years of its use. F.E.A makes it possible it evaluate a detail and complex structure, in a computer during the planning of the structure. The demonstration in the computer about the adequate strength of the structure and ISSN: Page 263

4 possibility of improving design during planning can justify the cost of this analysis work. F.E.A has also been known to increase the rating of the structures that were significantly over design and build many decades ago. The boundary conditions taken as a part of analysis are Temperature of -173 degree C. Convection along with Inner pressure of 0.7 MPa also with Vacuum pressure along the inner and outer tubes. V. ANALYSIS OF CRYOGENIC VESSEL The meshed model for the Cryogenic vessel is as shown in the Fig.2 Fig. 4 Equivalent Stress for the Cryogenic vessel The Equivalent Elastic Strain for the Cryogenic vessel is as shown in thefig5 Fig. 2 Meshed model of the Cryogenic vessel The Deformation for the Cryogenic vessel is as shown in the Fig. 3 Fig. 5 Equivalent Elastic Strain for the Cryogenic vessel Structural steel with Aluminium position The Temperature for the Cryogenic vessel Structural steel with Aluminium position is as shown in the Fig. 6 Fig. 3 Deformation of the Cryogenic vessel The Equivalent Stress for the Cryogenic vessel is as shown in the Fig. 4 Fig. 6 Temperature for the Cryogenic vessel The Total Heat flux for the Cryogenic vessel is as shown in the Fig. 7 ISSN: Page 264

5 Fig. 7 Total Heat flux for the Cryogenic vessel VI. CONCLUSIONS [7] Patel Pratik Kumar Baldev Bhai, Prof. Ronak Shah, Design and Optimization of Cryogenic Storage Vessel, IJEDR Volume 3, Issue 1, [8] The Cryogenic pressure vessel is modelled in Creo Parametric 2.0 and analysis is carried out in Ansys The analysis carried out is under static loading condition and also thermal base conditions. Different materials are being analysed for different conditions and materials used are Structural steel, Stainless steel, Aluminium and S- glass epoxy for the outer structure with aluminium, copper and stainless steel for the inner structure. Taking weight into consideration and stress into account, S- glass epoxy for the outer structure with aluminium for the inner structure is comparably better than the other materials. FUTURE SCOPE OF WORK Different composite materials can be analysed for various combinations of inner and outer structures. Various angle orientations can be imposed for all the composite materials. Shape optimisation can be done for various combinations taking the industrial standards into consideration. REFERENCES [1] E. Lisowski, M. Domagała, Simulation of liquid dynamics in a cryogenic mobile vessels, Insitute of Applied Informatics, Cracow University of Technology, al. Jana Pawła 37, [2] K. J. Jaya Kumar, Heat Transfer Analysis of Light Weight Cryogenic Tank for Space Vehicles, Indian Journal of Science and Technology, Vol 8(4), , February [3] SM. Aceves, J. Martinez-Frias, Garcia-Villazana, Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage, American Society of Mechanical Engineers International Mechanical Engineering Congress and Exposition Nashville, TN November 14-19, [4] Craig A. Stephens and Gregory J. Hanna, Thermal Modeling and Analysis of a Cryogenic Tank Design Exposed to Extreme Heating Profiles, NASA Contractor Report [5] S. M. Aceves, J. Martinez-Frias, Low Temperature and High Pressure Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage, O. Garcia-Villazana, FIMEE, Universidad de Guanajuato Salamanca, Gto. Mexico, Jan [6] A. Hima Bindu, Design and thermal analysis of cryogenic Fluid storage vessel, International Journal for Research in Applied Science & Engineering Technology (IJRASET), Special Issue-3, November 2014 ISSN: Page 265