Begell House Inc.
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
HTM
1093-3611
22
2-3
2018
Preface: Advances in Computational Heat Transfer (CHT-17)
v-vi
10.1615/HighTempMatProc.v22.i2-3.10
Oronzio
Manca
Dipartimento di Ingegneria Industriale e dell'Informazione, Università degli
Studi della Campania "Luigi Vanvitelli," Aversa (CE), Italy
Yogesh
Jaluria
Department of Mechanical and Aerospace Engineering Rutgers-New Brunswick, The State University of New Jersey Piscataway, NJ 08854, USA
INVESTIGATING THE USE OF PHASE-CHANGE MATERIALS FOR TEMPERATURE CONTROL DURING FAST FILLING OF HYDROGEN CYLINDERS
73-97
10.1615/HighTempMatProc.2018024731
Vishagen
Ramasamy
Faculty of Engineering and Environment, University of Southampton,
Southampton, UK
Edward S.
Richardson
Faculty of Engineering and Environment, University of Southampton,
Southampton, UK
Philippa
Reed
Faculty of Engineering and Environment, University of Southampton,
Southampton, UK
Warren
Hepples
Department of Research and Innovations, Luxfer Gas Cylinders, Nottingham,
UK
Andrew
Wheeler
Department of Engineering, University of Cambridge, Cambridge UK
compressed hydrogen storage
hydrogen cylinders
CFD
conjugate heat transfer model
phase-change materials
enhanced heat transfer
Toyota Mirai
This paper explores the use of phase-change materials in the process of fast filling of hydrogen cylinders in order to limit the rise in the gas temperature by enhancing heat transfer from the gas. It is necessary to limit the temperature rise because the structural performance of the cylinder materials can be degraded at higher temperatures. Initially, two computational approaches for modeling the
fast filling of hydrogen cylinders are presented and validated; the first is an axisymmetric computational
fluid dynamics simulation and the second is a single-zone approach with one-dimensional conjugate heat transfer through the cylinder walls. The models are applied to study fast filling of a hydrogen-powered passenger car. The predictions show that the minimum safe fill time for Type
III cylinders with aluminum liners is generally shorter than for Type IV cylinders with plastic liners, for given ambient and precooling temperatures. Alternatively, Type III cylinders require less precooling for a given fill time. Introduction of a phase-change material heat sink is assessed as a means of reducing the fill time for Type IV cylinders. Paraffin-based phase-change materials are considered. The predictions show that the use of pure paraffin wax does not help in reducing the gas temperature due to its low thermal conductivity, however materials with improved thermal conductivity, for example, mixtures of paraffin wax and graphite, can facilitate reduced fill times. Without use of phase-change material it is not possible to reduce the fill time of Type IV cylinders
below three minutes unless the gas supply is precooled. While the fill time can be reduced by precooling the gas supply, the phase-change material reduces the degree of precooling required for a given fill time by 10–20 K, and reduces the minimum theoretical power consumption of the cooler by 50–100%, depending on the ambient temperature.
SIMULATION OF HYPERSONIC FLOWS USING THE QGD-BASED PARALLEL PROGRAM COMPLEX "EXPRESS-3D"
99-113
10.1615/HighTempMatProc.2018024713
Evgeny V.
Shilnikov
Keldysh Institute of Applied Mathematics, Russian Academy of Sciences,
4 Miusskaya Sq., Moscow, 125047, Russia
Tatiana G.
Elizarova
Keldysh Institute of Applied Mathematics, Russian Academy of Sciences,
4 Miusskaya Sq., Moscow, 125047, Russia
explicit scheme
hypersonic flows
quasi-gasdynamical equations
shock-boundary layer interaction
This paper describes the experience gained in using a program complex "Express-3D." The program complex implies an explicit variant of kinetically consistent finite difference schemes based on the system of quasi-gasdynamical (QGD) equations. The system of QGD equations differs from the Navier-Stokes equations in specific additional dissipative terms. These terms serve as efficient numerical stabilizers. The used algorithm allows one to simulate gas flows in a wide range of Mach numbers with minimum changes in the program code. The new version of the program complex Express-3D uses multiblock nonorthogonal structured hexahedral grids. This allows one to solve complex geometry problems. Note that the computational algorithm for structured grids is usually much simpler than for widely used unstructured tetrahedral grids. The method of difference scheme construction on nonorthogonal grids is described. The program complex showed a good efficiency in solving a set of problems including those relating the subsonic and supersonic flows. Here we present the results of using the program complex for the hypersonic flow/boundary layer interaction problems. The simulation results are discussed and compared with known experimental data.
INNOVATIVE ELECTRIC OVENS FOR PIZZA BAKING: NUMERICAL THERMAL INVESTIGATION
115-140
10.1615/HighTempMatProc.2018024507
Biagio
Morrone
Dept. of Engineering DI – Università della Campania "Luigi Vanvitelli" – Aversa, (CE) 81031 – Italy
Mena
Ciarmiello
Department of Industrial and Information Technology Engineering, Università
della Campania Luigi Vanvitelli, Aversa, Italy
air pollution
dough baking
baking process
numerical methods
radiative
emissivity
The Neapolitan pizza is required to be baked in traditional wood-fired ovens, according to Specification of Production No. 56/2010. However, airborne and hazard pollutants due to wood combustion may lead to severe air quality impacts, thus design and development of electric oven, alternative
to wood-fired ones, is a suitable target for air pollution control strategies. In this paper, a three-dimensional Computational Fluid Dynamics (CFD) model has been developed to evaluate the thermal performances of an electric oven for baking Neapolitan pizzas. The developed CFD
model comprises the continuity, momentum, and energy equations, whereas the standard k−ε
approach is used for turbulence closure, and the surface-to-surface model is applied for radiative heat transfer mechanism. Coupled conduction–convection and radiation process is taken into account to assess the role of the walls bounding the cooking chamber in the heat transfer process. Electrical heaters located in the bed and dome walls of the cooking chamber provide the heat generation, allowing the baking of pizzas. A condition of full load oven is investigated, with nine pizzas placed on the bed of the baking chamber. Different thermophysical model properties
are investigated. The results highlight that the radiative heat transfer is the very predominant mechanism for pizza baking. Moreover, the effect of the surface pizza emissivity on the temperature time evolution is investigated, considering three different emissivity values. In addition, a comparison between the models with constant and variable thermophysical properties is carried out to scrutinize the validity of the effect of variable thermophysical properties on thermal baking performance.
COMPUTATIONAL STUDY OF HEAT TRANSFER CHARACTERISTICS OF SUPERCRITICAL METHANE FLOW IN THE COOLANT CHANNEL OF A ROCKET ENGINE
141-159
10.1615/HighTempMatProc.2018024725
Mathew Saxon
Arakkaparambil
Liquid Propulsion Systems Center, Indian Space Research Organisation,
Trivandrum 695547, Kerala, India
Pradeep
Kumar
Department of Aerospace Engineering, Indian Institute of Space Science
and Technology, Valiamal Road, Valiamala, Thiruvananthpuram, Kerala,
695547, India
Aravind
Vaidyanathan
Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Valiamal Road, Valiamala, Thiruvananthpuram, Kerala, 695547, India
methane
rocket engine coolant channel
regenerative cooling
supercritical
heat transfer deterioration
local flow acceleration
asymmetric heating
Liquid methane as a rocket fuel has promising prospects for deep space travel in the near future owing to its possible availability in alien planets. The major challenge however appears to be to properly address the issue of unusual heat transfer characteristics observed in the coolant channel at supercritical pressures, typically when the coolant fluid temperatures exceed a critical value. The current work systematically looks at the applicability of typical one-dimensional model to predict the heat transfer behavior in the coolant channel. The study then extends to a 2D numerical analysis and parametric investigation with an objective to study the effect of heat flux on heat transfer at a supercritical pressure. A 2D numerical analysis indicates that the one-dimensional approach is having limited applicability for heat transfer at a supercritical
pressure. A systematic study has been carried out in the current work to investigate the onset of heat transfer deterioration in rocket engine coolant channels which involves asymmetric heating. The study indicates that heat transfer deterioration can be expected as the heat flux is
increased and interestingly localized flow acceleration owing to sharp fall in density appears to have a prime influence on the heat transfer deterioration. An attempt has been made to look at some possible methods to offset the heat transfer deterioration, and the study reveals that providing higher surface roughness could be a simple possible means to overcome the heat transfer deterioration.
COMPUTATIONAL PROBLEMS OF THERMAL RADIATION IN AEROSPACE ENGINEERING
161-184
10.1615/HighTempMatProc.2018024755
Anouar
Soufiani
Laboratoire EM2C, CNRS, CentraleSupelec, Universite Paris Saclay, 3 rue Joliot Curie, 91192 Gif-sur-Yvette Cedex, France
Sophia
Haussener
Laboratory of Renewable Energy Science and Engineering, EPFL, Station 9, 1015 Lausanne, Switzerland
Leonid A.
Dombrovsky
Joint Institute for High Temperatures, 17A Krasnokazarmennaya Str., Moscow,
111116, Russia; Tyumen State University, 6 Volodarsky Str., Tyumen, 625003, Russia
heat transfer
thermal radiation
space vehicles
atmospheric re-entry
thermal protection
solar probe
This article reports on the three computational studies presented at the Radiation Panel of the 7th
International Symposium on Advances in Computational Heat Transfer (CHT-17), which focus on aerospace applications.
EVALUATION OF MODELS FOR COLLISIONAL SURFACE PRODUCTION WITHIN THE Σ–Y EULERIAN SPRAY ATOMIZATION MODEL
185-202
10.1615/HighTempMatProc.2018024610
Dominik
Eichler
Institute of Heat and Mass Transfer, RWTH Aachen University,
Augustinerbach 6, 52062 Aachen, Germany
Tim
Gronarz
Institute of Heat and Mass Transfer, RWTH Aachen University,
Augustinerbach 6, 52062 Aachen, Germany
Philipp
Pischke
Institute of Heat and Mass Transfer, RWTH Aachen University,
Augustinerbach 6, 52062 Aachen, Germany
Reinhold
Kneer
Institute of Heat and Mass Transfer, RWTH Aachen University, Augustinerbach 6, 52062 Aachen, Germany
Eulerian
spray
atomization
CFD
The Σ–Y Eulerian spray atomization model is suited for CFD simulations of high Weber and Reynolds number sprays. In this model, the spray is assumed to behave like a single phase turbulent flow. Two additional transport equations are introduced to describe the flow: A transport equation for the liquid mass fraction Y and another one for the surface density Σ. Among others, collisions of liquid droplets lead to production and destruction of Σ. In the work presented here, an expression for the collisional production term is evaluated by means of a numerical experiment featuring
turbulent droplet collisions and droplet breakup: Generic droplet populations, described by an initial mean Weber number, and the shape of the initial droplet distribution are subject to turbulent velocity fluctuations leading to turbulent droplet collisions and droplet breakup. A stochastic droplet collision modeling algorithm is used to trigger collisions. The outcome of a collision is determined
by a collision model proposed in the literature. Results show that a collisional production term can be obtained featuring the same form proposed in the literature which was hitherto postulated, but not demonstrated. Different approaches exist for the modeling parameters of the surface density production/destruction term. Therefore CFD simulations employing the Σ–Y model are performed applying different values for these parameters. The results indicate that especially the parameter concerning the equilibrium value for surface density has major influence.