An Experimental and Numerical Study of a Supersonic Overexpanded Jet Gas-Dynamic Structure

2013 ◽  
Vol 8 (4) ◽  
pp. 84-92
Author(s):  
Valeriy Zapryagaev ◽  
Ivan Kavun ◽  
Sergey Kundasev
Keyword(s):  
Experimental Data ◽  
Numerical Study ◽  
Numerical Data ◽  
Dynamic Structure ◽  
Ansys Fluent ◽  
Gas Dynamic ◽  
Factors Influencing ◽  
Calculation Results ◽  
Main Factors ◽  
Supersonic Overexpanded Jet

Experimental data about the structure of the supersonic overexpanded jet (Ma=3, n=0.58) is obtained. This data is intended for verification of numerical calculation results. Main factors influencing on the precision of experimental data are shown. Experimental results are supplemented with numerical simulation performed with program package ANSYS Fluent. Differences between experimental and numerical data are analyzed

Tools for Estimating Resonant Stresses in Turbine Blades

2007 ◽  
Author(s):  
A. M. Sipatov ◽  
N. V. Gladisheva ◽  
V. G. Avgustinovich ◽  
I. A. Povishev
Keyword(s):  
Experimental Data ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Mode Shapes ◽  
Ansys Software ◽  
Factors Affecting ◽  
Gas Dynamic ◽  
Calculation Results ◽  
Main Factors ◽  
Good Agreement

The problem of obtaining adequate aerodynamical boundary conditions for an analyzed blade is important to predict resonant stresses. According to this, three different CFD approaches of stator-rotor modeling have been investigated for obtaining gas dynamic loading: 1. 3D averaged and then quasi-3D unsteady calculations. 2. Fully 3D unsteady calculations using commercial CFX solver. 3. Fully 3D unsteady calculations using the in-house solver. To carry out 3D structural analysis the ANSYS software and our subroutines have been applied. The methodology to estimate damper ratio for the different mode shapes and mode numbers has been developed. As a result, the tools to predict the resonant stress have been created where we tried to take into account all main factors affecting resonant stress level. The HPT first stage blade of a modern aircraft engine was chosen as an example of using our tools for prediction of resonant stresses level. A comparison of experimental data and obtained calculation results showed good agreement.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

scholarly journals The Solutions to the Uncertainty Problem of Urban Fractal Dimension Calculation

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 453 ◽  
Author(s):  
Chen
Keyword(s):  
Fractal Dimension ◽  
Spatial Analysis ◽  
Fractal Geometry ◽  
Fractal Dimensions ◽  
Dimension Estimation ◽  
Scale Free ◽  
Factors Influencing ◽  
Calculation Results ◽  
Fractal Patterns ◽  
Main Factors

Fractal geometry provides a powerful tool for scale-free spatial analysis of cities, but the fractal dimension calculation results always depend on methods and scopes of the study area. This phenomenon has been puzzling many researchers. This paper is devoted to discussing the problem of uncertainty of fractal dimension estimation and the potential solutions to it. Using regular fractals as archetypes, we can reveal the causes and effects of the diversity of fractal dimension estimation results by analogy. The main factors influencing fractal dimension values of cities include prefractal structure, multi-scaling fractal patterns, and self-affine fractal growth. The solution to the problem is to substitute the real fractal dimension values with comparable fractal dimensions. The main measures are as follows. First, select a proper method for a special fractal study. Second, define a proper study area for a city according to a study aim, or define comparable study areas for different cities. These suggestions may be helpful for the students who take interest in or have already participated in the studies of fractal cities.

scholarly journals Experimental and Numerical Study on Supersonic Ejectors Working with R-1234ze(E)

2018 ◽  
Vol 180 ◽  
pp. 02047 ◽  
Author(s):  
Jan Kracik ◽  
Vaclav Dvorak ◽  
Vu Nguyen Van ◽  
Kamil Smierciew
Keyword(s):  
Numerical Study ◽  
Renewable Energy Sources ◽  
Electric Energy ◽  
Numerical Data ◽  
Working Fluid ◽  
Ansys Fluent ◽  
Environment Friendly ◽  
Fluent Software ◽  
Develop Environment ◽  
Good Agreement

These days, much effort is being put into lowering the consumption of electric energy and involving renewable energy sources. Many engineers and designers are trying to develop environment-friendly technologies worldwide. It is related to incorporating appropriate devices into such technologies. The object of this paper is to investigate these devices in connection with refrigeration systems. Ejectors can be considered such as these devices. The primary interest of this paper is to investigate the suitability of a numerical model for an ejector, which is incorporated into a refrigeration system. In the present paper, there have been investigated seven different test runs of working of the ejector with a working fluid R-1234ze(E). Some of the investigated cases seem to have a good agreement and there are no significant discrepancies between them, however, there are also cases that do not correspond to the experimental data at all. The ejector has been investigated in both on-design and off-design working modes. A comparison between the experimental and numerical data (CFD) performed by Ansys Fluent software is presented and discussed for both an ideal and a real gas model. In addition, an enhanced analytical model has been introduced for all runs of the ejector.

scholarly journals Numerical Study of the Hydrodynamics of Waves and Currents and Their Effects in Pier Scouring

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2256 ◽  
Author(s):  
Matias Quezada ◽  
Aldo Tamburrino ◽  
Yarko Niño
Keyword(s):  
Experimental Data ◽  
Relative Velocity ◽  
Numerical Study ◽  
Numerical Data ◽  
Navier Stokes ◽  
Shear Stresses ◽  
Numeric Modeling ◽  
Waves And Currents ◽  
Cylindrical Piles ◽  
The Waves

The scour around cylindrical piles due to codirectional and opposite waves and currents is studied with Reynolds Averaged Navier–Stokes (RANS) equations via REEF3D numeric modeling. First, a calibration process was made through a comparison with the experimental data available in the literature. Subsequently, not only the hydrodynamics, but also the expected scour for a set of scenarios, which were defined by the relative velocity of the current ( U C W ), were studied numerically. The results obtained show that the hydrodynamics around the pile for codirectional or opposite waves and currents not have significant differences when analyzed in terms of their velocities, vorticities and mean shear stresses, since the currents proved to be more relevant compared to the net flow. The equilibrium scour, estimated by the extrapolation of the numerical data with the equation by Sheppard, enabled us to estimate values close to those described in the literature. From this extrapolation, it was verified that the dimensionless scour would be less when the waves and currents are from opposite directions. The U C W parameter is an indicator used to adequately measure the interactions between the currents and waves under conditions of codirectional flow. Nevertheless, it is recommended to modify this parameter for currents and waves in opposite directions, and an equation is proposed for this case.

Analysis of Different Radiation Models in a Swirl Stabilized Combustor

2014 ◽  
Author(s):  
Aayush K. Sharma ◽  
Chandrachur Bhattacharya ◽  
Swarnendu Sen ◽  
Achintya Mukhopadhyay ◽  
Amitava Datta
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Computational Study ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Numerical Data ◽  
Ansys Fluent ◽  
Wall Functions ◽  
Radiation Modelling ◽  
Model Gas Turbine Combustor

A computational study on spray combustion, using kerosene (C12H23) as fuel, in a model gas turbine combustor has been carried out. The numerical modelling of radiation heat transfer is carried out in a three-dimensional swirl stabilized, liquid-fuelled combustor. The Favre-averaged governing equations are solved using Ansys Fluent 14.5 as the CFD package. The turbulence parameters are computed using realizable k-ε with standard wall functions model. Eulerian-Lagrangian approach is used to track stochastically the motion of the evaporation species in the continuous gas phase. The effect of different radiation models — Discrete Ordinate (DO), P1 and Discrete Transfer Radiation Model (DTRM) along with Soot are analysed in the present study. To validate the results of radiation modelling carried out in the present work, the computational results have been compared with previous experimental data for the same combustor geometry. The numerical data considering effect of soot along with radiation is shown to closely approximate the experimental data. An attempt has also been made to introduce a liner in the combustor and evaluate its effect and the heat transfer across the liner for the present numerical model.

Influencing Factors Analysis for Failure Risk of Upstream Revetment of Existing Levees

2011 ◽  
Vol 250-253 ◽  
pp. 2843-2847 ◽  
Author(s):  
Yan Hong Gao ◽  
Jun Zhi Zhang
Keyword(s):  
Risk Analysis ◽  
Influencing Factors ◽  
Load Effect ◽  
Factors Analysis ◽  
Factors Influencing ◽  
Failure Risk ◽  
Analysis Theory ◽  
Proposed Model ◽  
Calculation Results ◽  
Main Factors

According to risk analysis theory, a model of analysis for failure risk of upstream revetment of existing levees is proposed in this paper. Based on the model, the load effect and generalized resistance for the failure risk of upstream revetment of existing levees are analyzed, and then the influencing factors of the failure risk of upstream revetment are studied. The calculation results show that the proposed model is workable and effective for analysis of the failure risk of upstream revetment of existing levees, and the main factors influencing failure risk of existing upstream revetment are the randomness of the existing effective thickness of upstream revetment and ratio mean of upstream slope of the existing levees.

scholarly journals Using the Ansys Fluent for simulation of two-sided lid-driven flow in a staggered cavity

2012 ◽  
pp. 169-178
Author(s):  
Jelena Markovic ◽  
Natasa Lukic ◽  
Jelena Ilic ◽  
Branislava Nikolovski ◽  
Milan Sovilj ◽  
...  
Keyword(s):  
Numerical Study ◽  
Velocity Profiles ◽  
The Other ◽  
Ansys Fluent ◽  
Direction Parallel ◽  
Central Lines ◽  
Parallel Motion ◽  
Calculation Results ◽  
Existing Data ◽  
Good Agreement

This paper is concerned with numerical study of the two-sided lid-driven fluid flow in a staggered cavity. The ANSYS FLUENT commercial software was used for the simulation, In one of the simulated cases the lids are moving in opposite directions (antiparallel motion) and in the other they move in the same direction (parallel motion). Calculation results for various Re numbers are presented in the form of flow patterns and velocity profiles along the central lines of the cavity. The results are compared with the existing data from the literature. In general, a good agreement is found, especially in the antiparallel motion, while in the parallel motion the same flow pattern is found, but the velocity profiles are slightly different.

scholarly journals MATHEMATICAL MODEL OF LIQUID FUEL COMBUSTION IN THE APPARATUS

2020 ◽  
Vol 2018 (1) ◽  
pp. 173-174
Author(s):  
Larisa Kondrat'eva ◽  
Ol'ga Sverdlova
Keyword(s):  
Mathematical Model ◽  
Oxygen Concentration ◽  
Liquid Fuel ◽  
Organic Liquid ◽  
Material Balance ◽  
Fuel Combustion ◽  
Combustion Model ◽  
Factors Influencing ◽  
Calculation Results ◽  
Main Factors

The article deals with the mathematical combustion model of organic liquid fuel in the technological furnace. The main factors influencing on the process are considered. The formula for the calculation of the oxygen concentration at the reactionary surface is obtained. The material balance of oxygen including equations for the diffusive and dense parts is compiled. The calculation results are shown in the diagrams.

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