Comparison of the Ansys Fluent System Solvers for the Possibility of Supersonic Flow Solving at the Low Pressures

2019 ◽  
Vol 95 (1) ◽  
pp. 475-481
Author(s):  
Anna Maxová ◽  
Pavla Šabacká ◽  
Jiří Maxa
Author(s):  
Megan Higley ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner

Abstract In this work, a two-dimensional (2D) geometrically-accurate model of the TN-32 cask is generated in ANSYS/Fluent to investigate the effect of backfill gases and their pressures on the peak cladding temperature (PCT). This model is similar to the cask being used in high-burnup (HBU) spent fuel data project lead by the Electric Power Research Institute (EPRI). Helium, nitrogen, argon, and water vapor fill gases are investigated at pressures ranging from atmospheric (∼105 Pa) to 100 Pa. Steady-state computational fluid dynamics (CFD) simulations that include the effect of gas rarefaction (temperature-jump) at the gas-solid interfaces are conducted. The PCT as a function of heat generation rate and pressure is reported as well as the heat generation rate that brings the cladding temperature to the radial hydride formation limit. The results show that there are competing effects between the temperature-jump and the thermal conductivity of the gas to increase the fuel rods’ temperature. The low pressures increased the PCT, with the increase being most significant for the helium backfill.


Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6849
Author(s):  
Pavla Šabacká ◽  
Vilém Neděla ◽  
Jiří Maxa ◽  
Robert Bayer

Pumping in vacuum chambers is part of the field of environmental electron microscopy. These chambers are separated from each other by a small-diameter aperture that creates a critical flow in the supersonic flow regime. The distribution of pressure and shock waves in the path of the primary electron beam passing through the differentially pumped chamber has a large influence on the quality of the resulting microscope image. As part of this research, an experimental chamber was constructed to map supersonic flow at low pressures. The shape of this chamber was designed using mathematical–physical analyses, which served not only as a basis for the design of its geometry, but especially for the correct choice of absolute and differential pressure sensors with respect to the cryogenic temperature generated in the supersonic flow. The mathematical and physical analyses presented here map the nature of the supersonic flow with large gradients of state variables at low pressures at the continuum mechanics boundary near the region of free molecule motion in which the Environmental Electron Microscope and its differentially pumped chamber operate, which has a significant impact on the resulting sharpness of the final image obtained by the microscope. The results of this work map the flow in and behind the Laval nozzle in the experimental chamber and are the initial basis that enabled the optimization of the design of the chamber based on Prandtl’s theory for the possibility of fitting it with pressure probes in such a way that they can map the flow in and behind the Laval nozzle.


2018 ◽  
Vol 87 (1) ◽  
pp. 397-403
Author(s):  
Pavla Hlavatá ◽  
Jiří Maxa ◽  
Petr Vyroubal

Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.


2009 ◽  
Vol 129 (6) ◽  
pp. 831-839
Author(s):  
Keisuke Udagawa ◽  
Sadatake Tomioka ◽  
Hiroyuki Yamasaki

2020 ◽  
Vol 20 (3) ◽  
pp. 343-353
Author(s):  
Ngo Van He ◽  
Le Thi Thai

In this paper, a commercial CFD code, ANSYS-Fluent has been used to investigate the effect of mesh number generated in the computed domain on the CFD aerodynamic performances of a container ship. A full-scale model of the 1200TEU container ship has been chosen as a reference model in the computation. Five different mesh numbers for the same dimension domain have been used and the CFD aerodynamic performances of the above water surface hull of the ship have been shown. The obtained CFD results show a remarkable effect of mesh number on aerodynamic performances of the ship and the mesh convergence has been found. The study is an evidence to prove that the mesh number has affected the CFD results in general and the accuracy of the CFD aerodynamic performances in particular.


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