An injection cooling criterion was employed in the 2014 Dual Domain and Midplane flow solvers to improve the accuracy of the results around the local area of the injection location. This same injection cooling criterion has been adopted in the 3D flow solvers. The improved accuracy of the gate freeze time results in improved part shrinkage and warpage prediction.
The injection cooling criterion defines when the node associated with an injection cone starts to cool down. Once the part has filled, or a short-shot has occurred, the software checks to determine whether cooling can start at each injection location. The criterion is a very low flow rate value, sufficiently small that the subsequent influence of barrel temperature on the injection temperature is negligible. When the flow rate at the injection node falls below this criterion, for two consecutive time steps, the injection node starts to cool. Until that time, the node is considered to be at the melt temperature. Thus, different injection locations can start cooling at different times. Once a location has started cooling, it will continue cooling regardless of the flow rate.
With this enhancement, you will notice a convergence of the results returned by the different solvers, particularly for injection into hot runner nodes and beam nodes.