we are dealing with Hstars Brand heat exchangers, our water flow velocity in evaporator is about 2m/s, however, one of our customer told us that the speed is too much, that will cause cooper vibration, he told me a good and easy solution to reduce velocity at inlets is to increase the nozzle size.

However, I donot think 2m/s is too fast, anyone tell me what is the right velocity of flow rate?