Solidification simulation

A powerful FEM (Finite Element Method) program is used which simultaneously computes the complex 26-direction heat transfer between each block of a fine three-dimensional model of the solidifying metal.

The casting shape, sand mould and associated feeders and insulating materials are all incorporated into the model and a thermal analysis is carried out  which simulates the heat flow during the solidification of a casting. From this information the solidification progression is simulated resulting in an 'X-Ray' of the casting model which predicts any areas of unacceptable shrinkage.

Goodwin's are the only steel foundry to be audited and awarded a "best practice" certificate for "Computer Aided Methoding" by the UK Governments Energy Efficiency Office.

Computer Aided Design    

Goodwin use AutoCAD to produce detailed and concept design drawings as well as generating key data for input modelling software such as ANSYS for Finite Element Stress Analysis. So versatile is Computer Aided Design (CAD?) that many clients call on it to produce a model of what would only have previously been possible as an architects impression or concept.

Forgings can be re-designed to enable their manufacture as a casting, this can give cost and production time savings.

The picture shows a solid model of a 5000kg casting for a boiler pump used in power generating turbines.

ANSYS analysis

A computer aided engineering (CAE) system combining mechanical, structural, thermal, fluid dynamics can be used to aid the development of the correct casting shape to meet the component operational conditions.

The heat flow characteristics and resulting mechanical stress of castings during heat treatment or under operational conditions can be calculated and the casting design modified if required.

In one successful design project it was necessary to calculate the heat transfer coefficients from a steam path to the outer walls of a steam valve casting.

A fluid dynamics model was constructed using an ANSYS system. In the model steam was injected at the inlet of the valve at specified speed and pressure and allowed to pass through to the outlets.

Stress analysis

Casting designs can be verified using Solid Works modelling and ANSYS analysis.

In the model shown it was necessary to see how the stress levels varied through the section of the valve body.

Various load cases were considered, with differing working pressures applied to the entire internal surface of the valve In these simulations additional pressure forces were placed on the faces of the inlet and outlet nozzles to ensure that there was an equilibrium of forces in the lateral direction.  The resultant model showing the constraints and pressure forces indicated by the colour gradient is shown.

By carrying out this work, coupled with stress rupture testing of the material, it was possible to demonstrate the suitability of the design for ultra-supercritical application.