Computational Fluid Dynamic Applications for Jet Propulsion System Integration

1991 ◽  
Vol 113 (1) ◽  
pp. 40-50 ◽  
Author(s):  
R. H. Tindell
Keyword(s):  
System Integration ◽  
Fluid Dynamic ◽  
Low Cost ◽  
Separated Flow ◽  
Propulsion System ◽  
Navier Stokes ◽  
Aerospace Vehicles ◽  
Design Engineers ◽  
Flow Phenomena ◽  
The Impact

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.

scholarly journals Computational Fluid Dynamic Applications for Jet Propulsion System Integration

1990 ◽  
Author(s):  
R. H. Tindell
Keyword(s):  
System Integration ◽  
Fluid Dynamic ◽  
Low Cost ◽  
Separated Flow ◽  
Propulsion System ◽  
Navier Stokes ◽  
Aerospace Vehicles ◽  
Design Engineers ◽  
Flow Phenomena ◽  
The Impact

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.

scholarly journals Numerical analysis of high-lift configurations with oscillating flaps

2021 ◽  
Author(s):  
Johannes Ruhland ◽  
Christian Breitsamter
Keyword(s):  
Reynolds Number ◽  
Flow Separation ◽  
Separated Flow ◽  
Navier Stokes ◽  
Rotational Axis ◽  
High Lift ◽  
Hinge Point ◽  
Reduced Frequency ◽  
Flap Deflection ◽  
The Impact

AbstractThis study presents two-dimensional aerodynamic investigations of various high-lift configuration settings concerning the deflection angles of droop nose, spoiler and flap in the context of enhancing the high-lift performance by dynamic flap movement. The investigations highlight the impact of a periodically oscillating trailing edge flap on lift, drag and flow separation of the high-lift configuration by numerical simulations. The computations are conducted with regard to the variation of the parameters reduced frequency and the position of the rotational axis. The numerical flow simulations are conducted on a block-structured grid using Reynolds Averaged Navier Stokes simulations employing the shear stress transport $$k-\omega $$ k - ω turbulence model. The feature Dynamic Mesh Motion implements the motion of the oscillating flap. Regarding low-speed wind tunnel testing for a Reynolds number of $$0.5 \times 10^{6}$$ 0.5 × 10 6 the flap movement around a dropped hinge point, which is located outside the flap, offers benefits with regard to additional lift and delayed flow separation at the flap compared to a flap movement around a hinge point, which is located at 15 % of the flap chord length. Flow separation can be suppressed beyond the maximum static flap deflection angle. By means of an oscillating flap around the dropped hinge point, it is possible to reattach a separated flow at the flap and to keep it attached further on. For a Reynolds number of $$20 \times 10^6$$ 20 × 10 6 , reflecting full scale flight conditions, additional lift is generated for both rotational axis positions.

scholarly journals Numerical Analysis of Thermal and Aerodynamic Fields in a Channel with Cascaded Baffles

2017 ◽  
Vol 62 (1) ◽  
pp. 16 ◽  
Author(s):  
Younes Menni ◽  
Ahmed Azzi
Keyword(s):  
Fluid Dynamic ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Turbulent Regime ◽  
Transfer Coefficients ◽  
Computational Fluid Dynamic Analysis ◽  
Heat Transfer Coefficients ◽  
Discretization Algorithm ◽  
Volume Method ◽  
The Impact

A computational fluid dynamic analysis of thermal and aerodynamic fields for an incompressible steady-state flow of a Newtonian fluid through a two-dimensional horizontal rectangular section channel with upper and lower wall-attached, vertical, staggered, transverse, cascaded rectangular-triangular (CRT), solid-type baffles is carried out in the present paper using the Commercial, Computational Fluid Dynamics, software FLUENT. The flow model is governed by the Reynolds averaged Navier-Stokes (RANS) equations with the SST k-ω turbulence model and the energy equation. The finite volume method (FVM) with the SIMPLE-discretization algorithm is applied for the solution of the problem. The computations are carried out in the turbulent regime for different Reynolds numbers. In this study, thermo-aeraulic fields, dimensionless axial profiles of velocity, skin friction coefficients, local and average heat transfer coefficients, and thermal enhancement factor were investigated, at constant surface temperature condition along the heated upper wall of the channel, for all the geometry under investigation and chosen for various stations. The impact of the cascaded rectangular-triangular geometry of the baffle on the thermal and dynamic behavior of air is shown and this in comparing the data of this obstacle type with those of the simple flat rectangular-shaped baffle. This CFD analysis can be a real application in the field of heat exchangers, solar air collectors, and electronic equipments.

Modeling and Analysis of Main Flow–Shroud Leakage Flow Interaction in LP Turbines

2006 ◽  
Author(s):  
Jochen Gier ◽  
Karl Engel ◽  
Bertram Stubert ◽  
Ralf Wittmaack
Keyword(s):  
Main Flow ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
Leakage Flow ◽  
Modeling And Analysis ◽  
Simplified Approach ◽  
Leakage Flows ◽  
Flow Phenomena ◽  
Flow Effects ◽  
The Impact

Endwall losses significantly contribute to the overall losses in modern turbomachinery, especially when aerodynamic load and pressure ratios are increased. In turbines with shrouded airfoils a large portion of these losses are generated by the leakage flow across the shroud clearance. For the design of modern jet engine turbines it becomes increasingly important to include the impact of shroud leakage flows in the aerodynamic design. There are two main aspects connected to this issue. The first aspect is to optimize the cavity flow and its interaction with the main flow. The second aspect is to perform the airfoil design with boundary conditions, which include the shroud leakage flow effects. In comparison to the simplified approach of neglecting the real endwall geometry and leakage flow this should enable the designer to produce improved airfoils for the entire span. In order to address the second aspect of supporting the airfoil design with improved shroud leakage consideration within the airfoil design process, an efficient procedure for modeling the shroud leakage flow has been implemented into the design Navier-Stokes code. The intention is to model the major leakage flow phenomena without the necessity of pre-defining all details of the shroud geometry. In the paper the results of this model are compared to conventional computations, computations with mesh-resolved cavities and experimental data. The differences are discussed and the impact of certain configuration aspects are analyzed.

Optimization of Liquid Steel Flow in an Industrial Tundish

2013 ◽  
Vol 634-638 ◽  
pp. 1752-1755
Author(s):  
Qiu Fang Tong ◽  
Zhong Hua Wu ◽  
Arun S. Mujumdar
Keyword(s):  
Liquid Steel ◽  
Nonmetallic Inclusions ◽  
Fluid Dynamic ◽  
Numerical Results ◽  
Dead Volume ◽  
Flow Phenomena ◽  
Steel Flow ◽  
The Impact ◽  
Novel Design ◽  
Slag Entrapment

A computational fluid dynamic (CFD) model was developed to study the fluid flow phenomena taking place in an industrial tundish. Numerical results showed spatial distributions of the velocity vectors, the residence time and fields of turbulence kinetic energy. Selected computer simulation results were validated with experimental data. The effect of the impact pad and interior dams on the hydrodynamics of liquid steel flow were studied numerically and optimized to reduce the fraction of dead volume zones and augment nonmetallic inclusions to float into the slag. A novel design of a turbo-stopper was proposed and its function to decelerate the ladle shroud jet and direct the flow back to reduce slag entrapment was discussed. Such numerical results improved our understanding of the hydrodynamics of liquid steel flow in the tundish and contribute to an optimized operation.

Engine Cycle Selection and Propulsion System Integration for Future High Performance Fighter Aircraft

1977 ◽  
Author(s):  
G. W. Lind ◽  
J. Protopapas
Keyword(s):  
System Integration ◽  
High Performance ◽  
Low Cost ◽  
Propulsion System ◽  
Fighter Aircraft ◽  
Performance Constraints ◽  
Design Variables ◽  
And Performance ◽  
Time Required ◽  
Engine Cycle

The selection and optimization of propulsion systems can be a costly and time-consuming process, especially when there are diverse performance requirements placed on the overall weapon system. Computerized procedures have been developed within the Grumman Propulsion Department to mechanize this capability and yet maintain the man-m-the-loop for full visibility during the evaluation of a candidate design concept. The system permits low cost, rapid, multidiscipline. interactive engine cycle selection and propulsion system integration to be effectively performed early in the preliminary design process of a high performance fighter aircraft. For example, the computer running time required to select a point design within a matrix of design variables and performance constraints has been reduced by 85 percent over previous techniques. This paper describes these propulsion evaluation procedures and cites a specific example of their application to the analysis of an advanced interceptor requirement.

scholarly journals Numerical Investigation of Design and Operating Parameters of Thermal Gradient Continuous-Flow PCR Microreactor Using One Heater

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 919
Author(s):  
Usama Perwez ◽  
Imran Aziz ◽  
Faisal Ahmed ◽  
Mohsin Raza Khan
Keyword(s):  
Parametric Study ◽  
System Integration ◽  
Continuous Flow ◽  
Point Of Care ◽  
Low Cost ◽  
Operating Parameters ◽  
Substrate Thickness ◽  
Chip Design ◽  
Diagnostics System ◽  
The Impact

To respond to the dire need for miniaturization and process simplification of continuous-flow PCR (CF-PCR) device, this paper represents design and operation guide of a novel metal alloy assisted hybrid microdevice (polydimethylsiloxane (PDMS) and glass) for CF-PCR employing one heater. In this research, the specific objectives are to determine whether one heater chip design will be flexible enough when the size of DNA base pair is varied and to investigate whether one heater CF-PCR device will be able to resolve the longstanding problem of thermal crosstalk. Furthermore, the parametric study is performed to determine which of the fourteen parameters have the greatest impact on the performance of one heater CF-PCR device. The main objective of this parametric study is to distinguish between the parameters that are either critical to the chip performance or can be freely specified. It is found that substrate thickness, flow rate, channel spacing, aspect ratio, channel pass length and external heat transfer coefficient are the most limiting parameters that can either improve or deteriorate the chip’s thermal performance. Overall, the impact of design and operating parameters are observed to be least on thermocycling profile at low Reynolds number (≤0.37 Re). However, in addition to the primary metric advantages of CF-PCR, one heater chip design helps in minimizing the thermal crosstalk effects by a factor of 4 in comparison to dual heater PCR while still maintaining a critical criteria of chip flexibility in terms of handling various sizes of DNA fragments. Hence, the proposed scheme paves the way for low-cost point-of-care diagnostics, system integration, and device miniaturization, realizing a portable microfluidic device applicable for on-site and direct field uses.

scholarly journals A low—storage Runge—Kutta OpenFOAM solver for compressible low—Mach number flows: aeroacoustic and thermo—fluid dynamic applications

2019 ◽  
Vol 128 ◽  
pp. 10001
Author(s):  
Valerio D’Alessandro ◽  
Matteo Falone ◽  
Luca Giammichele ◽  
Sergio Montelpare
Keyword(s):  
Sound Propagation ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Time Integration ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Central Schemes ◽  
Thermal Boundary Conditions ◽  
Finite Volume Approach ◽  
The Impact

A solver for compressible Navier–Stokes equations is presented in this paper. Low-storage RungeKutta schemes were adopted for time integration; on the other hand the finite volume approach available within OpenFOAM library has been adopted for space discretization. Kurganov-Noelle-Petrova approach was used for convective terms, while central schemes for diffusive ones. The aforementioned techniques were selected and tested in order to allow the possibility of solving a broad range of physical phenomena with particular emphasis to aeroacoustic and thermo-fluid dynamic problems. Indeed, that standard OpenFOAM solution techniques produce an unacceptable dissipation for acoustic phenomena computations. Non–reflective boundary treatment was also considered to avoid spurious numerical reflections. The reliability and the robustness of the solver is proved by computing several benchmarks. Lastly, the impact of the thermal boundary conditions on the sound propagation was analyzed.

On the Impact of Blade Count Reduction on Aerodynamic Performance and Loss Generation in a Three-Stage LP Turbine

2001 ◽  
Author(s):  
Jochen Gier ◽  
Sabine Ardey
Keyword(s):  
Low Pressure ◽  
Aerodynamic Performance ◽  
Point Of View ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Local Flow ◽  
Wide Range ◽  
Separation Bubbles ◽  
Flow Phenomena ◽  
The Impact

Reducing the number of blades in low pressure turbines is a desirable option for decreasing total operation costs. From an aerodynamical point of view this directly leads to an increased blade load. However, increasing the blade load above a certain level results in viscous effects like separation bubbles and finally full separation. This becomes especially significant for aero engine turbines, which operate at high altitudes and thus low Reynolds numbers. The underlying local flow phenomena and the effect on the aerodynamic performance of such configurations are addressed in this paper. This investigation is based on a three-stage low pressure turbine typical for aero engines. Different setups are employed with different number of guide vanes in certain stages. Furthermore, the Reynolds number is varied within a wide range. These configurations are investigated numerically using a modern steady-state transitional Navier-Stokes solver and experimental results from the same turbine. Based on this information, a detailed analysis of the viscous flow phenomena is performed with focus on the influence of separation bubbles on the loss production after the transition. These results are discussed with respect to blade count reduction.

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

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