Method and apparatus for modeling injection of a fluid in a mold cavity

A method for modeling injection of a fluid into a mold defining a three dimensional cavity, the method comprising the steps of:

• (a) providing a three dimensional computer model defining the cavity;
• (b) discretizing a solution domain based on the model;
• (c) specifying boundary conditions;
• and
• (d) solving for process variables using conservation of mass, conservation of momentum, and conservation of energy equations for at least a portion of the solution domain, wherein:
• step (b) comprises the substep of generating a finite element mesh based on the model by subdividing the model into a plurality of connected elements defined by a plurality of nodes;
• step (d) comprises the substep of determining a location of a solid/liquid interface, the determination of the interface comprising the substep of determining locations at which a process variable achieves a given value;
• and
• step (d) further comprises the substep of removing from the solution domain nodes corresponding to elements which contain no unfrozen material.

An apparatus for modeling injection of a fluid into a mold defining a three dimensional cavity, the apparatus comprising:

• a memory for storing code that defines a set of instructions;
• and
• a processor for executing said set of instructions to:
• (a) discretize a solution domain based on a three dimensional computer model defining a cavity;
• and
• (b) solve for process variables using conservation of mass, conservation of momentum, and conservation of energy equations, wherein an explicit scheme is used to solve the conservation of energy equation and wherein the explicit scheme comprises a thermal clock that varies locally and may proceed differently than a global clock.

An apparatus for modeling injection of a fluid into a mold defining a three dimensional cavity, the apparatus comprising:

• a memory for storing code that defines a set of instructions;
• and
• a processor for executing said set of instructions to:
• (a) discretize a solution domain based on a three dimensional computer model defining a cavity;
• (b) generate a finite element mesh based on the model by subdividing the model into a plurality of connected elements defined by a plurality of nodes;
• (c) solve for process variables using conservation of mass, conservation of momentum, and conservation of energy equations for at least a portion of the solution domain;
• (d) determine a location of a solid/liquid interface by determining locations at which a process variable achieves a given value;
• and
• (e) remove from the solution domain nodes corresponding to elements which contain no unfrozen material.