I was surprised that this came out so well, an awesome water-down-the-drain sound in my very own kitchen sink. A plastic dishpan was tipped and held there until the water exited. Quite a roar, unmodified except that it is contained in the dish washing file.
This is the sound of silica gel being put in water. The chemical reaction can be heard acoustically, but this was recorded with a hydrophone into a zoom h4n. Have fun.