scholarly journals Characteristics Analysis of Dual Bell Nozzle using Computational Fluid Dynamics

2019 ◽  
Vol 4 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Yeasir Mohammad Akib ◽  
Asif Kabir ◽  
Mahdi Hasan
Keyword(s):  
Imaging Technique ◽  
Space Exploration ◽  
Ansys Fluent ◽  
Space Tourism ◽  
Nozzle Contour ◽  
Different Types ◽  
Characteristics Analysis ◽  
Flow Through ◽  
Developed Nations ◽  
Dual Bell

Space exploration and space tourism have now become a raging competition among the developed nations. For this reason, different types of advanced rocket nozzles with prospective privileges are introduced. Altitude adaptive dual bell nozzle will soon replace the conventional nozzles for the first stage rocket launcher. Indeed, this nozzle has auto adaption capability based on altitude. The major feature of a dual bell nozzle is the two bell-shaped contours separated by an inflection point. This nozzle has left rooms for researchers to test different flight conditions and transition characteristics. In this paper, a dual bell nozzle contour has been developed in MATLAB and analysed for different thermodynamic parameters. ANSYS Fluent is used in analysing flow through the nozzle. Shadowgraph imaging technique is used for measuring density gradient and compared it with fluent results. The simulations were performed by using the k-epsilon turbulence model.

scholarly journals EFFECT OF CAVITIES SHAPES ON THE ROUGHNESS FRICTION FACTOR IN PERFORATED AND SLOTTED HORIZONTAL WELLS USED TO DEWATER OPENCAST MINES

2018 ◽  
pp. 9-13
Author(s):  
Duc Huan Tran ◽  
Carsten Drebenstedt
Keyword(s):  
Pressure Drop ◽  
Mining Industry ◽  
Horizontal Wells ◽  
Wall Friction ◽  
Ansys Fluent ◽  
Friction Factors ◽  
Different Types ◽  
Opencast Mines ◽  
Flow Through ◽  
High Reynolds

The horizontal wells have been adapted to use for dewatering purpose in the mining industry. Due to unique characteristics, those horizontal filters are rec-ommended to utilize not only the mechanical strength but also the hydraulic per-formance. Pressure drop along the horizontal well is a major factor that affects the performance of a wellbore. The pressure drop incurs due to four separate effects: wall friction, perforation roughness, inflow acceleration and mixing ef-fects. This work presents the effects of the two first factors in perforated or slot-ted pipes, which correspond to the case of no flow through the wall. Numerical analysis was carried out with different types of perforations and slots. The simu-lated model accomplished using ANSYS Fluent 14.5. The results revealed that at high Reynolds number, the roughness friction factors in circular perforated pipes are significantly greater than those in axial slotted pipes and perpendicular slotted pipes.

Computational fluid dynamic analysis of the exhaust gas flow through absorptive and reactive mufflers: some case studies

2016 ◽  
Vol 231 (11) ◽  
pp. 1568-1588 ◽  
Author(s):  
Sushovan Chatterjee
Keyword(s):  
Dynamic Analysis ◽  
Computational Fluid Dynamic ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Exhaust Gas ◽  
Computational Fluid Dynamic Analysis ◽  
Ansys Fluent ◽  
Different Types ◽  
Flow Through

This paper aims to study comprehensively the flow characteristics of exhaust gases through different types of muffler (e.g. absorptive, reactive and resonating). Geometric models were designed using PRO-E and analysed using ANSYS FLUENT 14. The contours for the pressure, the velocity and the turbulence were plotted for optimization of the muffler design based on the known thermodynamic parameters. On the basis of the variation in these parameters, various hybrid designs were proposed for a muffler and even for a combination of mufflers.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

Modeling Heat and Mass Transfer Correlations for Flow Through Micro Channels in Monolith Honeycomb Catalytic Combustor

2009 ◽  
Author(s):  
Juan Yin ◽  
Yi-wu Weng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Catalytic Combustion ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Predicting Performance ◽  
Micro Channels ◽  
Characteristics Analysis ◽  
Flow Through ◽  
Catalytic Combustor

This paper investigated performance characteristics analysis of catalytic combustion by utilizing 1-D models incorporated heat and mass transfer correlations. The 1-D numerical results were compared with 2-D models studies and experimental data. The performance characteristics were mainly the effects of operating conditions on methane conversion rate. The comparable analysis confirmed that 1-D model can success in predicting performance of catalytic combustion when empiric inter-phase heat and mass transfer correlations are used and appropriate operating conditions are chosen.

scholarly journals Space tourism: for or against?

2021 ◽  
pp. 64-68
Author(s):  
Yevhenii Melnyk
Keyword(s):  
Space Exploration ◽  
Environmental Problems ◽  
Negative Consequences ◽  
Environmental Challenges ◽  
Space Tourism

This work presents a group of activities based on the didactic materials dealing with issues related to space exploration in general and space tourism in particular. These activities aimed at developing receptive and productive skills allow students studying French at B2 level to consider a variety of topics (current and emerging environmental problems; the international community’s response to environmental challenges; negative consequences of space conquest), organize active use and efficient acquisition of thematic vocabulary, improve students’ ability to present and argue their own position.

scholarly journals Simulation and Modeling of Flow in a Gas Compressor

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Anna Avramenko ◽  
Alexey Frolov ◽  
Jari Hämäläinen
Keyword(s):  
Steady State ◽  
Mass Flow ◽  
Gas Flow ◽  
Simulation Method ◽  
High Mass ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Low Mass ◽  
Flow Through

The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

Pulse Converters—A Method of Improving the Performance of the Turbocharged Diesel Engine

1973 ◽  
Vol 187 (1) ◽  
pp. 635-647 ◽  
Author(s):  
M. S. Janota ◽  
N. Watson
Keyword(s):  
Pulse Generator ◽  
Test Results ◽  
Turbocharged Diesel Engine ◽  
Turbine Efficiency ◽  
Different Types ◽  
Partial Admission ◽  
Characteristics Analysis ◽  
Pulse Converter ◽  
Flow Loss ◽  
Loss Coefficients

Today, most turbocharged diesel engines operate on the pulse system. This is most effective on those engines whose exhaust manifolds can connect groups of three cylinders to a turbine entry without scavenging interference, e.g. three-, six-, nine- and twelve-cylinder engines. However, when only two cylinders can be connected to each turbine entry, e.g. four-, eight- and sixteen-cylinder engines, without interference, the system is usually less efficient. This is because the widely fluctuating, partial admission turbine conditions lower the average turbine efficiency. Recently, the pulse converter has been developed to improve the performance of such engines. A detailed investigation into the operation and application of the pulse converter has been conducted. Test results from three completely different types of engines showed substantial improvements in performance. The dependence of the pulse converter on engine speed and load, the effect of area variations in the pulse converter and the timing of the interfering exhaust pressure waves have been studied. A comparison of theoretically predicted and measured transient pressures (from a model pulse converter fitted to a pulse generator) was made. The theoretical analysis is based on empirical steady-flow loss coefficients and forms a boundary condition for a method of characteristics analysis. Results are compared with those predicted by the simple constant-pressure theory.

Flow Across a Butterfly Valve in a Dam Penstock

2017 ◽  
Author(s):  
Dominic Lattouf ◽  
B. P. Huynh
Keyword(s):  
Navier Stokes ◽  
Butterfly Valve ◽  
Maximum Torque ◽  
Ansys Fluent ◽  
Water Head ◽  
Models Comparison ◽  
Flow Through ◽  
Volume Method ◽  
Grid Independence ◽  
Valve Angle

Butterfly valves are typically used as emergency closure devices in dam penstocks; these valves must be capable of closing if a penstock bursts. This paper summarizes a 3D CFD (Computational Fluid Dynamics) study that was conducted on the water flow across a sizable butterfly valve (1.6m in diameter) in a dam penstock with 57m of water head. The main aim is to determine the maximum torque required to close the valve. Thus semi steady flow conditions across the valve at various degrees of closure were investigated and the corresponding torque calculated. A maximum torque of about 87 700 N-m has been obtained, occurring at valve angle 40° (with valve totally closed at 0°, and fully open at 90°). Visual results were analyzed at each valve angle to understand the nature of the flow through the butterfly valve using various 2D contours and streamline images. The CFD software ANSYS Fluent has been used employing a Finite Volume Method. The RANS (Reynolds-Averaged Navier-Stokes) approach with Realizable K-epsilon turbulence model was employed. A grid independence study with up to 10 million cells has also been carried out, resulting in the adoption of 7.5 million cells in all models. Comparison with other available data was also completed, adding to the reliability of the computational results. Distribution of pressure, flow velocity, and turbulence parameters are also presented.

Computational Study of the Downpull Force on High-Head Slide Gates

2019 ◽  
Author(s):  
Juan C. Arango Escobar ◽  
David Calderon Villegas ◽  
Aldo Benavides Moran ◽  
Alejandro Molina Ochoa
Keyword(s):  
Computational Study ◽  
Maximum Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Flow Through ◽  
High Head ◽  
The One ◽  
Bottom Outlet

Abstract This paper presents CFD simulations of the flow through a real bottom outlet equipped with high-head slide gates. The operating head of the gates and the maximum flow rate are 70 m and 650 m3/s, respectively. The numerical simulations were performed in ANSYS-FLUENT version 19.2. VOF method was used to model the free surface flow downstream the slide gates. Hydrodynamic forces were calculated at nine gate openings for a standard 45° lip gate; the downpull coefficients obtained from the simulations were compared with estimates from Naudascher’s analytical method. According to the CFD results, the downpull force acting on the 45° lip gate is 5%–10% lower than the one estimated analytically for the analyzed gate positions. Additionally, the flow through an inverted 30° lip gate was simulated to estimate the downpull coefficient at various gate openings. These coefficients cannot be determined analytically. The methodology here described can easily be applied to different gate geometries for which design coefficients are not available.

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