Stress Engineering has used computational fluid dynamics (CFD) to simulated liquid filling in a wider variety of industries, including pharmaceuticals, foods, skin care products, and cleaning products. We have helped our clients optimize their filling processes to increase throughput while reducing or even eliminating foaming.
The figures below show the results of three different fill-rate profiles. In each plot the red area is liquid; the blue is air. The left plot shows that filling at a constant rate causes severe splashing which will entrain air in the liquid and cause foaming. On the other end of the spectrum, filling can be done over the same period of time by starting from zero flow rate and ramping up to a high rate at the end of the filling cycle. Results of this process are shown in the center. In this case the high flow rate required at the end of filling causes a depression to be blown into the surface of the liquid. This forces air into the pool of fluid already in the container and generates foaming. Results at the right show the preferred filling profile. Here the filling rate is low at the beginning and steps to a higher rate 20% into the cycle. This lays a pool of fluid into the container at low speed to avoid splashing. This pool cushions the later high-speed flow. With proper profiling of the fill rate, throughput can be maintained and foaming avoided.