water wetter is some super neato stuff. I'm not sure what is in it to give its properties. But basically what it does is lower or and even virtaually eliminate the water's surface tension which greatly reduces the thickness of the boundry layer flow. The surface tension of water or even anti-freeze coolant mix causes the coolant to leave voids in areas where it turns sharp corners inside the water jackets. The surface tension (what makes water bead up) acts all the time, what happens is when the water flows ocer a surface there is a certain thickness of water that "clings" to the surface and becasue of this clinging the water moves very slowly. This boundry layer is also not easily disturbed. SO basically the coolant sticks to the insides of the engine and can casue what is referred to as boundry layer boiling where the coolant can boil in an area about 1/8 to 1/16 inch deep in the hot areas of the engine. In extreme conditions these local boiling spots can boil so violently that they actually turn to a froth almost eliminating heat transfer to the coolant through conduction and now the area is cooling mostly by convection. The boundry layer phenomenom also exists inside the radiator where due to the boundry layer flow the majority of the flow of hot coolant is not in direct contact with the tubes of the radiator, instead the hot water must transfer its heat to the surface of the tube through this thin boundry layer flow which is terribly inefficent.
Water Wetter reduces this tendency. Addition of water wetter to the coolant can increase the capacity of the cooling system by up to 25% by improving heat transfer.
Boundry layer flow is both a blessing and a curse depending on the environment. In the cooling system of an engine it is a curse, but the boundry layer flow can also be used to insulate critical components from heat. Boundry layer flow is utilized inside turbine engine turbine sections. Here boundry layer air flows are used to sourround the turbine and turbine inlet vanes. This layer of relatively cool air protects the vanes from the exhasut gasses that are hotter than the melting point of the material the vanes are made of.
