scholarly journals Specific Features of Flow on Compression Surfaces of a Convergent Air Intake

2022 ◽  
Vol 16 (2) ◽  
pp. 29-40
Author(s):  
S. A. Akinin ◽  
A. V. Starov

The results of computational and experimental studies of a model of a hypersonic convergent air intake are presented. Experimental studies were carried out in a hot-shot wind tunnel IT-302M SB RAS at a Mach number M = 5.7 and an angle of attack α = 4 °. Numerical modeling was carried out in a three-dimensional setting in the ANSYS Fluent software package. The calculations were carried out in 4 versions using different turbulence models: k-ɛ standard, RNG k-ɛ, k-ɷ standard and k-ɷ SST. The features of the flow structure are established. The pressure distributions on the compression surfaces and in the air intake channel are obtained. The separated flow at the entrance of the inner channel was studied. It was found that the use of various turbulence models has a significant effect on the size and position of separation. The best agreement between the calculated and experimental data on the level of static pressure was shown by the variant with the k-ɛ standard turbulence model.

1963 ◽  
Vol 16 (4) ◽  
pp. 620-632 ◽  
Author(s):  
D. J. Maull ◽  
L. F. East

The flow inside rectangular and other cavities in a wall has been investigated at low subsonic velocities using oil flow and surface static-pressure distributions. Evidence has been found of regular three-dimensional flows in cavities with large span-to-chord ratios which would normally be considered to have two-dimensional flow near their centre-lines. The dependence of the steadiness of the flow upon the cavity's span as well as its chord and depth has also been observed.


2018 ◽  
Vol 56 (3) ◽  
pp. 370
Author(s):  
Nguyen Van Thang ◽  
Ha Tien Vinh ◽  
Bui Dinh Tri ◽  
Nguyen Duy Trong

This article carries out the numerical simulation of airflow over three dimensional car models using ANSYS Fluent software. The calculations have been performed by using realizable k-e turbulence model. The external airflow field of the simplified BMV M6 model with or without a wing is simulated. Several aerodynamic characteristics such as pressure distribution, velocity contours, velocity vectors, streamlines, turbulence kinetic energy and turbulence dissipation energy are analyzed in this study. The aerodynamic forces acting on the car model is calculated and compared with other authors.


2014 ◽  
Vol 984-985 ◽  
pp. 1210-1213
Author(s):  
G. Srinivas ◽  
Srinivasa Rao Potti

The vent or opening is called nozzle. The objectives are to measure the flow rates and pressure distributions within the converging and diverging nozzle under different exit and inlet pressure ratios. Analytic results will be used to contrast the measurements for the pressure and normal shock locations. In this paper computational Fluid Dynamics (CFD) Analysis of various performance parameters like static pressure, the Mach number, intensity of turbulence, the area ratio are studied in detail for a rocket nozzle from Inlet to exit by using Ansys Fluent software. From the public literature survey the geometry co-ordinates are taken. The throat diameter and exit and diameter are same for all nozzles. After the simulation the results revealed that the divergence angle varies the mach number and other performance parameters also varies. For smaller nozzle angle the discharge coefficient increases with increasing pressure ratio until the choked condition is reached for varying the divergence angle.


2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Allan I. J. Love ◽  
Donald Giddings ◽  
Henry Power

The turbulent flow through a 3D diffuser featuring a double expansion is investigated using computational fluid dynamics. Time dependent simulations are reported using the stress omega Reynolds stress model available in ANSYS FLUENT 13.0. The flow topography and characteristics over a range of Reynolds numbers from 42,000 to 170,000 is reported, and its features are consistent with those investigated for other similar geometries. A transition from a chaotic separated flow to one featuring one large recirculation in one corner of the diffuser is predicted at a Reynolds number of 80,000. For a Reynolds number of 170,000 a precessing/flapping motion of the main flow field was identified, the frequency of which is consistent with other numerical and experimental studies.


2013 ◽  
Vol 8 (2) ◽  
pp. 119-127 ◽  
Author(s):  
D. K. Chibwe ◽  
G. Akdogan ◽  
P. Taskinen

Abstract Typical current operation of lateral-blown Peirce-Smith converters (PSCs) has the common phenomenon of splashing and slopping due to air injection. The splashing and wave motion in these converters cause metal losses and potential production lost time due to intermittent cleaning of the converter mouth and thus reduced process throughput. Understanding of the effect of combined top and lateral blowing could possibly lead to alternative technology advancement for increased process efficiency. In this study, computational fluid dynamics (CFD) simulations of conventional common practice (lateral blowing) and combined (top and lateral blowing) in a PSC were carried out, and results of flow variables (bath velocity, turbulence kinetic energy, etc.) were compared. The two-dimensional (2-D) and three-dimensional (3-D) simulations of the three-phase system (air–matte–slag) were executed utilizing a commercial CFD numerical software code, ANSYS FLUENT 14.0. These simulations were performed employing the volume of fluid and realizable turbulence models to account for multiphase and turbulent nature of the flow, respectively. Upon completion of the simulations, the results of the models were analysed and compared by means of density contour plots, velocity vector plots, turbulent kinetic energy vector plots, average turbulent kinetic energy, turbulent intensity contour plots and average matte bulk velocity. It was found that both blowing configuration and slag layer thickness have significant effects on mixing propagation, wave formation and splashing in the PSC as the results showed wave formation and splashing significantly being reduced by employing combined top- and lateral-blowing configurations.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Kumar Subramanian ◽  
Günter Wozny

Modelling of the hydrodynamics behaviour of the liquid on the corrugated sheets of packing is studied using three-dimensional, volume-of-fluid (VOF) model that is incorporated in Ansys Fluent 12.0. The flow of three different liquids with different physical properties is modelled. A domain of corrugated sheets of packing resembling the real structured packing with little modifications in the elementary geometry is constructed using ICEM CFD 12.0. The quantitative comparisons of the wetting behavior from the simulations are in good agreement with experiments. Further, the study has been extended to understand the influence of the second corrugated sheet on the flow behavior. The contours from the simulations indicate the liquid hold-up in the crimp of two corrugated sheets, and these results are in good agreement with the earlier experimental studies performed using X-ray tomography in the literature. The result from the simulation shows that even for the high flow rate of around 811 mL/min for silicon-oil (DC5), only 60% of the corrugated sheet has been wetted. Hence, the efficiency of the existing packing can be further increased by increasing the wetted area in the corrugated sheet of packing.


2018 ◽  
Vol 12 (4) ◽  
pp. 4300-4328
Author(s):  
Pasymi Pasymi ◽  
Y. W. Budhi ◽  
A. Irawan ◽  
Y. Bindar

Flow structure inside a chamber greatly determines the process performances. Therefore, the flow structure inside a chamber are often constructed in such a way as an effort to obtain equipment performances in accordance with the expectations. This study explored flow structure inside several chamber geometries and operating conditions. Three types of chamber, namely; GTC, DTC and TJC were set as the investigated chambers. The Computational Fluid Dynamics technique, supported by some experimental data from the literature, is used as an investigation method. The RANS based models, under Ansys-Fluent software were used in this numerical investigation. Simulation results revealed that the flow structures of GTC and DTC are predominantly created by spiral and vortex patterns. The vortex stabilizer diameter in the GTC affects the vortex pattern, velocity profile and pressure drop. The flow structure of DTC presents the most complex behavior. The flow structure inside TJC, in the case of unconfined outlet boundary, is characterized by the helical and wavy jet pattern. This structure is determined by the initial tangential intensity (IIT) and the inlet aspect ratio (RIA). The structures of vortex, helical, and wavy axial flow are properly constructed and visualized in this paper. There is no a turbulence model which is always superior to the other models, consistently. The standard k-ε model exhibits the realistic and robust performances among  all of investigatied cases.


Author(s):  
D.-W. Kim ◽  
Youn J. Kim

The effects of casing shape on the performance and the interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are performed for the circular casing. Comparison of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.


Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1488 ◽  
Author(s):  
Marschik ◽  
Dörner ◽  
Roland ◽  
Miethlinger ◽  
Schöppner ◽  
...  

Wave-dispersion screws have been used industrially in many types of extrusion processes, injection molding, and blow molding. These high-performance screws are constructed by replacing the metering section of a conventional screw with a melt-conveying zone consisting of two or more parallel flow channels that oscillate periodically in-depth over multiple cycles. With the barrier flight between the screw channels being selectively undercut, the molten resin is strategically forced to flow across the secondary flight, assuring repeated cross-channel mixing of the polymer melt. Despite the industrial relevance, very few scientific studies have investigated the flow in wave-dispersion sections in detail. As a result, current screw designs are often based on traditional trial-and-error procedures rather than on the principles of extrusion theory. This study, which was split into two parts, was carried out to systematically address this issue. The research reported here (Part A) was designed to reduce the complexity of the problem, exclusively analyzing the pressure-induced flows of polymer melts in wave sections. Ignoring the influence of the screw rotation on the conveying characteristics of the wave section, the results could be clearly assigned to the governing type of flow mechanism, thereby providing a better understanding of the underlying physics. Experimental studies were performed on a novel extrusion die equipped with a dual wave-channel system with alternating channel depth profiles. A seminumerical modeling approach based on network theory is proposed that locally describes the downchannel and cross-channel flows along the wave channels and accurately predicts the pressure distributions in the flow domain. The solutions of our seminumerical approach were, moreover, compared to the results of three-dimensional non-Newtonian CFD simulations. The results of this study will be extended to real screw designs in Part B, which will include the influence of the screw rotation in the flow analysis.


Author(s):  
Alessandro Nocente ◽  
Tufan Arslan ◽  
Torbjørn K. Nielsen

The present work reviews a comparison between calculations of a steady and unsteady three dimensional (3D) flow past the diffuser channels of a centrifugal pump. The commercial software ANSYS Fluent has been used. The considered domain is one of the three stages, since each has exactly the same design. In the first part, simulations are carried out at the best efficiency point (BEP) both steady and transient state, single phase flow and four different turbulence models. Results are compared with the performance report from the manufacturer. In the second part, only the realizable k-ε turbulence model has been taken into account. The simulations have been repeated for different mass flows and the results were again compared with the data from the manufacturer. The comparison performed in the first part shows that integral quantities results are not sensibly influenced by the turbulence model. The comparison at different mass flow shows that the steady state simulations demonstrated to be a good approximation of the transient state, always containing the error within an acceptable limit. The minor computational effort needed makes it attractive to be used for further investigations which will involve two-phase flow studies on the same pump.


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