These set of calculators provide you with the average flow velocity, volumetric flow rate and Reynolds number applicable to your heat transfer fluid flow or for any other liquid phase system. There are a limited number of inputs required – the volumetric flowrate of the thermal fluid in your system, your pipe internal diameter, and the kinematic viscosity of your fluid.  You can use the data you obtain to maintain flow assurance in your system, size pumps and determine if you need to transition from a laminar flow regime to a turbulent one for optimal heat transport rates.