NX CAE UPDATE

[Mathi K]

 

NX CAE Sales Win - Aerospace

Customer name: Beijing 501 institute (China)

Main business: Manufacturing of Shenzhou spacecraft series, Remote sensing satellite, etc.

Customer situation prior NX CAE purchased:

1.           Customer’s CAD system is Pro/Engineering

2.           Existing I-deas TMG users (since year 2001)

3.           Need more thermal analyses for all product lines

Key requirements:

1.           Predict electric systems’ main failure modes under severe aerospace environment including radiation

2.           Efficient solution to simulate more thermal-stress coupled analyses

3.           Shorten modeling time

Competition: MSC

Why Siemens wins:

1.           I-deas TMG was considered the standard tool for the thermal/radiation analysis for satellites.

2.           They can leverage their existing I-deas TMG users’ experiences.

3.           Replaced MSC Nastran seats  with NX Nastran because of its tight integration with NX Space System Thermal (same as TMG)/ESC and NX Advanced FEM

4.           Strong customer relationship

NX CAE products the customer bought:

1.    NX Nastran

2.    NX Space System Thermal

 

 

High speed rotational flow – NX Advanced Flow

In this example, we simulate high speed fluid flow in an industrial compressor turbine using the rotating frame of reference (RFR) method.

Before any CFD simulation can be performed, it is necessary that a fluid domain is created to represent the volume or empty space in-between the complex parts of the equipment. This task is usually deemed as the most difficult to establish since the equipment parts are of complex shapes, and the slightest gaps will have a critical pressure effect in the flow results. With NX Synchronous Technology, creating fluid volumes have never been easier than just a couple of mouse clicks. Atop of that, the fluid volume remains associative to the CAD model of the equipment. This simply means any geometry changes to the CAD model will update the fluid volume automatically.

 

Turbulence is a key issue in CFD simulation, and especially in high speed flow. Hence, it is necessary to define a turbulence model to mimic its random and chaotic behavior in 3-dimensional air space. Depending on the CFD problem, NX Advanced Flow solver offers a variety of turbulence models to choose from.

·        None-Laminar Flow

·        Fixed Turbulent Viscosity

·        Mixed Length

·        K-Epsilon

·        Shear Stress Transport – SST

·        K-Omega

In this particular example, we utilize the K-Epsilon model which is also commonly known as the 2-equation turbulence model where the equations for k (turbulent kinetic energy) and ε (turbulent dissipation) are evaluated at every fluid node. Hence, the turbulent viscosity is not assumed constant throughout the fluid mesh domain which offers a much more accurate model of fluid turbulence.

High Speed Flow - NX Advanced Flow solver offers the option for high speed flow to accommodate highly compressible fluid flows above Mach 1, which automatically modifies the energy equation for rotating flows. In respect to this, supersonic inlets can also be defined when necessary. Additionally, viscous heating effects and transient pressure terms are also taken into account in the energy equations.

Moving Frames of Reference - The rotating frame of reference function allows definition of the rotation axis and the operating RPM, with the coriolis effect and centrifugal fluid forces automatically accounted for in this solution. For this particular case, the turbine air volume is specified as the rotating region however, if solids are defined, shear forces at the fluid/solid interface is automatically accounted for.

Results – Here is the analysis result showing velocity distribution of the compressor turbine, which could help to validate and optimize the product design.

The original technical paper is available for you. Please contact a CAE Top Gun in your country if you want the document.

 

 

 

 

WARM REGARDS

 

MATHI KRISHNAN