Experimental and numerical examination of an opposed jet RIM mix head at process conditions

The fluid jet impingement in the mix head for a reaction injection molding (RIM) is examined using flow visualization, laser Doppler anemometer measurements, and steady and unsteady finite volume simulations using boundary fitted non-orthogonal coordinates. Similar flow cases show a central flow impingement point and, away from the impingement point at the higher viscosity fluid is seen to form a surface that the lower viscosity fluid did not penetrate. A significant reduction of the areas of recirculation above the impingement region and stability of the flow field for some conditions of restriction resulted. General guidelines for stabilized flow and hence improve mixing are presented.