Numerical Analysis of the Wave Topping Unit for Small Turbojet

2010 ◽  
Author(s):  
Janusz Piechna ◽  
Rafael Cerpa ◽  
Staniszewski Marcin ◽  
Pezhman Akbari ◽  
Norbert Mu¨ller
Keyword(s):  
Numerical Analysis ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Wave Rotor ◽  
High Rotational Speed ◽  
Machine Performance ◽  
Flow Features ◽  
The Common ◽  
Analysis Models

The paper is focused on the numerical analysis of a wave topping unit used in a small turbojet engine. The analysis focuses on a four-port reverse flow (RF) wave rotor. The special feature of the considered wave rotor is its very high rotational speed. The wave rotor is connected directly with the common shaft between compressor and turbine, thus, the effects of Coriolis accelerations become important. In this study, first a one-dimensional model is used to estimate geometry of the wave rotor and port timings. Then, multi-dimensional analysis models are employed to predict the different flow characteristics inside the wave rotor channels. Three-dimensional flow features that reduce machine performance and influence rotor blade and duct wall thermal loads are identified.

Numerical Analysis of the Deterministic Stresses Associated to Impeller-Tongue Interactions in a Single Volute Centrifugal Pump

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
J. M. Fernández Oro ◽  
J. González ◽  
R. Barrio Perotti ◽  
M. Galdo Vega
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Centrifugal Pump ◽  
Turbulence Intensity ◽  
Three Dimensional ◽  
Relevant Information ◽  
Three Dimensional Flow ◽  
Deterministic Analysis ◽  
Starting Point ◽  
Flow Features

In this paper, a deterministic stress decomposition is applied over the numerical three-dimensional flow solution available for a single volute centrifugal pump. The numerical model has proven in previous publications its robustness to obtain the impeller to volute-tongue flow interaction, and it is now used as starting point for the current research. The main objective has been oriented toward a detailed analysis of the lack of uniformity in the flow that the volute tongue promotes on the blade-to-blade axisymmetric pattern. Through this analysis, the fluctuation field may be retrieved and main interaction sources have been pinpointed. The results obtained with the deterministic analysis become of paramount interest to understand the different flow features found in a typical centrifugal pump as a function of the flow rate. Moreover, this postprocessing tool provides an economic and easy procedure for designers to compare the different deterministic terms, also giving relevant information on the unresolved turbulence intensity scales. Complementarily, a way to model the turbulent effects in a systematic way is also presented, comparing their impact on the performance with respect to deterministic sources in a useful framework, that may be applied for similar kinds of pumps.

Numerical Study on Supersonic Combustor with an Allotype Cavity

2014 ◽  
Vol 694 ◽  
pp. 187-192
Author(s):  
Jin Xiang Wu ◽  
Jian Sun ◽  
Xiang Gou ◽  
Lian Sheng Liu
Keyword(s):  
Alternative Model ◽  
Numerical Study ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Experimental Result ◽  
Navier Stokes ◽  
Cold Flow ◽  
Hypersonic Inlet ◽  
Good Agreement

The three-dimensional coupled explicit Reynolds Averaged Navier–Stokes (RANS) equations and the two equation shear-stress transport k-w (SST k-w) model has been employed to numerically simulate the cold flow field in a special-shaped cavity-based supersonic combustor. In a cross-section shaped rectangular, hypersonic inlet with airflow at Mach 2.0 chamber, shock structures and flow characteristics of a herringbone-shaped boss and a herringbone-shaped cavity models were discussed, respectively. The results indicate: Firstly, according to the similarities of bevel-cutting shock characteristics between the boss case and the cavity case, the boss structure can serve as an ideal alternative model for shear-layer. Secondly, the eddies within cavity are composed of herringbone-spanwise vortexes, columnar vortices in the front and main-spanwise vortexes in the rear, featuring tilting, twisting and stretching. Thirdly, the simulated bottom-flow of cavity is in good agreement with experimental result, while the reverse flow-entrainment resulting from herringbone geometry and pressure gradient. However, the herringbone-shaped cavity has a better performance in fuel-mixing.

Aerodynamic Behavior of Asymmetric Jets in 3-D Furnaces

1994 ◽  
Author(s):  
F. M. El-Mahallawy ◽  
M. A. Hassan ◽  
M. A. Ismail ◽  
H. Zafan
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Numerical Experiments ◽  
Recirculation Zone ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Region ◽  
Stabilization Method ◽  
Flow Features

The purpose of this paper is to present and evaluate numerical experiments illustrating the flow features in a 3-D furnace utilizing unconventional asymmetrical jet that creates natural recirculation zone. The numerical simulation of this aerodynamic stabilization method have unveiled the three-dimensional nature of the flow pattern which possesses a quite large reverse flow region. The size and strength of the built recirculation zone would be capable of stabilizing the burning of low-quality fuels.

scholarly journals Effect of Impeller Parameters on the Flow inside the Centrifugal Blower using CFD

2020 ◽  
Vol 8 (6) ◽  
pp. 3977-3980
Keyword(s):  
Numerical Analysis ◽  
Stokes Equations ◽  
Control Volume ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Computational Domain ◽  
Centrifugal Blower ◽  
Impeller Blade ◽  
Navier Stokes Equations

A numerical analysis is carried out to understand the flow characteristics for different impeller configurations of a single stage centrifugal blower. The volute design is based on constant velocity method. Four different impeller configurations are selected for the analysis. Impeller blade geometry is created with point by point method. Numerical simulation is carried out by CFD software GAMBIT 2.4.6 and FLUENT 6.3.26. GAMBIT work includes geometry definition and grid generation of computational domain. This process includes selection of grid types, grid refinements and defining correct boundary conditions. Processing work is carried out in FLUENT. The viscous Navier-Stokes equations are solved with control volume approach and the k-ε turbulence model. In this three dimensional numerical analysis is carried out with steady flow approach. The rotor and stator interaction is solved by mixing plane approach. Results of simulation are presented in terms of flow parameters, at impeller outlet and various angular positions inside the volute. Also, the contours of flow properties are presented at the outlet plane of fluid domain. Results suggest that for the same configurations of centrifugal blower, as we change geometrical parameter of impeller the flow inside the blower get affected.

Experimental and numerical investigation of interactions between above and below ground drainage systems

2013 ◽  
Vol 67 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Slobodan Djordjević ◽  
Adrian J. Saul ◽  
Gavin R. Tabor ◽  
John Blanksby ◽  
Istvan Galambos ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Urban Areas ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Sewer Pipes ◽  
Drainage Systems ◽  
Flow Features ◽  
Below Ground ◽  
Set Up ◽  
Flood Flow

This paper presents the results of the experimental and numerical investigation of interactions between surface flood flow in urban areas and the flow in below ground drainage systems (sewer pipes and manholes). An experimental rig has been set up at the Water Engineering Laboratory at the University of Sheffield. It consists of a full scale gully structure with inlet grating, which connects the 8 m2 surface area with the pipe underneath that can function as an outfall and is also further connected to a tank so that it can come under surcharging conditions and cause outflow from the gully. A three-dimensional CFD (Computational Fluid Dynamics) model has been set up to investigate the hydraulic performance of this type of gully inlet during the interactions between surface flood flow and surcharged pipe flow. Preliminary results show that the numerical model can replicate various complex 3D flow features observed in laboratory conditions. This agreement is overall better in the case of water entering the gully than for the outflow conditions. The influence of the surface transverse slope on flow characteristics has been demonstrated. It is shown that re-circulation zones can form downstream from the gully. The number and size of these zones is influenced by the transverse terrain slope.

Numerical Analysis on Temperature Field of Electric Connectors

2014 ◽  
Vol 852 ◽  
pp. 602-607
Author(s):  
Yan Yan Luo ◽  
Yi Wen ◽  
Liang Hao ◽  
Xin Wei Liu ◽  
Yi Jun Wang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Temperature Field ◽  
Numerical Analysis ◽  
Environmental Temperature ◽  
Three Dimensional ◽  
Internal Heat ◽  
Solid Model ◽  
Monitoring Test ◽  
Convection Cooling ◽  
Analysis Models

The steady-state thermal analysis models are established based on the thermal analysis of the Electric connectors. With the consideration to the internal heat conduction and the convection cooling, the three-dimensional solid model is imposed by the reasonable loads and boundary conditions and analyzed by ANSYS thermal analysis module. The numerical analysis is made on the temperature field of a certain type of Electric connectors at different environmental temperature and different working current. The simulation results are compared with the monitoring test data.

Radial Ultra-Micro Wave Rotors (UµWR): Design and Simulation

2006 ◽  
Author(s):  
Florin Iancu ◽  
Janusz Piechna ◽  
Norbert Mu¨ller
Keyword(s):  
Reverse Flow ◽  
Three Dimensional ◽  
Axial Flow ◽  
Wave Rotor ◽  
Compression Process ◽  
Radial Wave ◽  
Wave Rotors ◽  
Commercial Code ◽  
Through Flow ◽  
Computational Fluid Dynamics Cfd

It has been shown that the wave rotor technology has the potential of improving the performance of gas turbine cycles. Moreover the radial wave rotor is an additional innovation for this technology. Unlike the commercialized axial-flow wave rotor (Comprex®), a radial one has the benefit of using centrifugal forces to improve the compression process or flow scavenging. The geometry of the rotor is much simpler and is ideal for microfabrication, which is relying mainly on two-dimensional processes to create three-dimensional features. This paper is presenting several radial ultra-micro wave rotors (UμWR) configurations and numerical analysis of these rotors. In a radial placement, the wave rotor has four possible configurations: two - general configuration, through-flow and reverse-flow, and each of these could have the low pressure air port positioned at inside or outside of the rotor. Results have been obtained using FLUENT, a Computational Fluid Dynamics (CFD) commercial code. The vast information about the unsteady processes occurring during simulation is visualized.

Evaluation of Non-Cavitating Steady State Performance of an Aero-Engine Gear Pump by Numerical Methods

2017 ◽  
Author(s):  
Shivakumar Ulaganathan ◽  
Ch. Kanna Babu ◽  
Girish Kalyanrao Degaonkar
Keyword(s):  
Numerical Analysis ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Internal Flow ◽  
Operating Conditions ◽  
Gear Pump ◽  
Design Features ◽  
Flow Features ◽  
Gear Pumps ◽  
Aero Engines

External gear pumps are typically used in aero-engines for the fuel and lubrication system due to its simplicity in construction. The design of the gear pump has been considerably improved over several years by including design features to improve its overall performance and reliability. In this paper, three-dimensional numerical analysis of an external gear was carried out by including design features such as scallops at the inlet and outlet, radial and axial clearances, journal bearing clearances and the axial tilt of the supporting bushes. The Immersed Solid Method (ISM) is used to analyze the gear pump at different operating conditions. The applicability of different turbulence models to the Immersed solid method is discussed. The internal flow features are discussed and compared with the results available in the literature. The Pump characteristics curve developed from the numerical analysis using the Immersed solid method (ISM) is compared with the experimental test results.

Flow Characteristics Within and Downstream of Spherical and Cylindrical Dimple on a Flat Plate at Low Reynolds Numbers

2004 ◽  
Author(s):  
A. Khalatov ◽  
A. Byerley ◽  
D. Ochoa ◽  
Seong-Ki Min
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Patterns ◽  
Flow Features ◽  
Laminar And Turbulent Flow ◽  
Low Reynolds ◽  
Oscillation Frequencies

A comprehensive experimental study has been performed in the U.S. Air Force Academy water tunnel to obtain a better understanding of the complicated flow patterns in shallow dimple configurations (h/D ≤ 0.1), including single cylindrical and spherical dimples, as well as single spanwise rows of dimples. The flow patterns, in-dimple separation zone extent, and bulk flow oscillation frequencies have been measured at low Reynolds number conditions. Three different single dimples and two single rows of dimples have been tested over a range of Reynolds numbers ReD of 3,170 to 23,590 including laminar and turbulent flow patterns downstream of a dimple. To visualize the fine flow features, five different colors of dye were injected through five cylindrical ports machined at locations upstream and inside the dimples. The measured results revealed unsteady and three-dimensional flow features inside and downstream of the dimple. The Reynolds number, dimple shape and the presence of adjacent dimples all play important roles in determining the nature of the flow pattern formation. Some preliminary conclusions regarding the laminar-turbulent flow transition after a dimple are presented.

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