Hi, I hope this is the right section. I'm trying to figure out a rough estimate of the pressure drop in a spiral heat exchanger. The fluids both being water. My guess it it would be in terms of the surface area of the inside of the heat exchanger, and the flow rate, but I can't seem to nail anything down. I should be able to figure out the actual heat conduction from one fluid to another on my own. I just need the pressure drop. I've found relationships between pressure drop and flow, but those are for round pipes, and don't seem to be applicable here. I could be wrong. Any advice you can give me would help a lot (this isn't homework). It doesn't need to be particularly precise, but if it was, that would be great. I'd be glad to have a ballpark figure.