Low Order Modeling for Fan and Outlet Guide Vanes in Aero-Engines

Intakes of reduced length have been proposed with the aim of producing aero-engines with higher efficiency and reduced weight. As the intake length decreases, it is expected that stronger effects of the fan on the flow over the intake lip will be seen. If the effects of the fan cannot be ignored, a low-cost but still accurate fan model is of great importance for designing a short-intake. In this paper, a low order rotor/stator model, the immersed boundary method with smeared geometry (IBMSG), has been further developed and validated on a rig test case. The improved IBMSG is more robust than the original. The rig test case used for validation features a low-pressure compression system with a nonaxisymmetric inflow, which is representative of the inlet condition of an aero-engine at its cruise condition. Both the fan and the outlet guide vanes (OGVs) are modeled using IBMSG. A detailed analysis is carried out on the flow both upstream and downstream of the fan. After validating the IBMSG method against the rig test case, a short-intake case, coupled with a fan designed for the next generation of aero-engines, is further investigated. It is found that compared with the intake-alone case, the inflow distortion at the fan face is significantly reduced by the presence of fan. Due to this increased interaction between the fan and the flow over the intake lip, accounting for the effects of the downstream fan is shown to be essential when designing a short intake.

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Low Order Modelling for Fan and Outlet Guide Vanes in Aero-Engines

Volume 2C: Turbomachinery ◽

10.1115/gt2018-75660 ◽

2018 ◽

Cited By ~ 1

Author(s):

Jiahuan Cui ◽

Rob Watson ◽

Paul Tucker ◽

Mark Wilson

Keyword(s):

Detailed Analysis ◽

Immersed Boundary Method ◽

Low Cost ◽

Immersed Boundary ◽

Test Case ◽

Guide Vanes ◽

Compression System ◽

Aero Engine ◽

Aero Engines ◽

Low Order

Intakes of reduced length have been proposed with the aim of producing aero-engines with higher efficiency and reduced weight. As the intake length decreases, it is expected that stronger effects of the fan on the flow over the intake lip will be seen. If the effects of the fan cannot be ignored, a low-cost but still accurate fan model is of great importance for designing a short-intake. In this paper, a low order rotor/stator model — the immersed boundary method with smeared geometry (IBMSG), has been further developed and validated on a rig test case. The improved IBMSG is more robust than the original. The rig test case used for validation features a low-pressure compression system with a non-axisymmetric inflow, which is representative of the inlet condition of an aero-engine at its cruise condition. Both the fan and the Outlet Guide Vanes (OGV) are modelled using IBMSG. Detailed analysis is carried out on the flow both upstream and downstream of the fan. After validating the IBMSG method against the rig test case, a short-intake case, coupled with a fan designed for the next generation of aero-engines, is further investigated. It is found that, compared with the intake-alone case, the inflow distortion at the fan face is significantly reduced by the presence of fan. Due to this increased interaction between the fan and the flow over the intake lip, accounting for the effects of the downstream fan is shown to be essential when designing a short intake.

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An Immersed Boundary Method for Simulation of Wind Flow Over Complex Terrain

Journal of Solar Energy Engineering ◽

10.1115/1.4004899 ◽

2011 ◽

Vol 134 (1) ◽

Cited By ~ 16

Author(s):

S. Jafari ◽

N. Chokani ◽

R. S. Abhari

Keyword(s):

Immersed Boundary Method ◽

Complex Terrain ◽

Stokes Equations ◽

Ground Level ◽

Rectangular Domain ◽

Immersed Boundary ◽

Test Case ◽

Wind Flow ◽

Wall Functions ◽

Boundary Method

The accurate modeling of the wind resource over complex terrain is required to optimize the micrositing of wind turbines. In this paper, an immersed boundary method that is used in connection with the Reynolds-averaged Navier–Stokes equations with k-ω turbulence model in order to efficiently simulate the wind flow over complex terrain is presented. With the immersed boundary method, only one Cartesian grid is required to simulate the wind flow for all wind directions, with only the rotation of the digital elevation map. Thus, the lengthy procedure of generating multiple grids for conventional rectangular domain is avoided. Wall functions are employed with the immersed boundary method in order to relax the stringent near-wall grid resolution requirements as well as to allow the effects of surface roughness to be accounted for. The immersed boundary method is applied to the complex terrain test case of Bolund Hill. The simulation results of wind speed and turbulent kinetic energy show good agreement with experiments for heights greater than 5 m above ground level.

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The Data Driven Surrogate Model Based Dynamic Design of Aero-Engine Fan Systems

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4049504 ◽

2021 ◽

Author(s):

Yunpeng Zhu ◽

Jie Yuan ◽

Zi-Qiang Lang ◽

Christoph W. Schwingshackl ◽

Loic Salles ◽

...

Keyword(s):

Surrogate Model ◽

System Analysis ◽

Data Driven ◽

Design Parameters ◽

Contact Friction ◽

Test Case ◽

Arx Model ◽

Analysis And Design ◽

Aero Engine ◽

Aero Engines

Abstract High cycle fatigue failures of fan blade systems due to vibrational loads are of great concern in the design of aero engines, where energy dissipation by the relative frictional motion in the dovetail joints provides the main damping to mitigate the vibrations. The performance of such a frictional damping can be enhanced by suitable coatings. However, the analysis and design of coated joint roots of gas turbine fan blades are computationally expensive due to strong contact friction nonlinearities and also complex physics involved in the dovetail. In this study, a data driven surrogate model, known as the Nonlinear in Parameter AutoRegressive with eXegenous input (NP-ARX) model, is introduced to circumvent the difficulties in the analysis and design of fan systems. The NP-ARX model is a linear input-output model, where the model coefficients are nonlinear functions of the design parameters of interest, such that the Frequency Response Function (FRF) can be directly obtained and used in the system analysis and design. A simplified fan bladed disc system is considered as the test case. The results show that by using the data driven surrogate model, an efficient and accurate design of aero-engine fan systems can be achieved. The approach is expected to be extended to solve the analysis and design problems of many other complex systems.

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