The turbulence effects lead to a higher rate of “mixing” within the flow and therefore increase the heat transfer rates significantly. When the Reynolds-number exceeds a value of 2300 a turbulent flow can be assumed. Based on the actual value of the Reynold-number the calculation will continue, either for a laminar (Re=2300), as these two states of the flow have a considerably different behavior: Turbulent pipe flow The Reynolds number is an important quantity that allows to predict the flow-state of the fluid. In a next step the Reynolds-number for the pipe flow will be calculated: It is the ratio of the viscosity (momentum diffusivity) and the thermal diffusivity and therefore important for this calculation. Based on these the so called Prandtl-number is calculated. Therefore it is necessary to calculate major characteristic parameters that are used to describe the flow state of the fluid.Īfter you have selected the type of fluid and its temperature, HTflux determines the relevant properties of your fluid: density, thermal conductivity, heat capacity, kinetic viscosity and the thermal diffusivity. The heat transfer from a flowing fluid to the inner surface of the pipe/tube strongly depends on the actual state of the flow. Pipe flow and heat transfer physics – brief overviewĪs HTflux will do the calculation for you, you will not have to dig into fluid dynamics, however the major calculation steps will be outlined in the following paragraphs. Use this boundary condition along with the correct average temperature in your simulation to calculate the heat transfer of your pipe flow. By clicking on the “OK” button the value will be assigned for the boundary condition selected. for PE pipes usually a roughness of 0.003 mm is specified.Īfter providing the desired parameters HTflux will calculate the surface resistance value of the pipes heat-transfer. Pipe roughness: you can provide the absolute roughness of the pipe here, e.g.Smooth pipe model: based on Prandtl calculation.

Nikuradse: based on sand-grain roughness.Colebrook-White: leave this as default if you are unsure.Friction model: you are able to pick of three different friction models for the calculation:.Flow-speed: you can specify the average flow-speed in m/s here, the flow rate will be calculated accordindly.Flow rate: you can specify the flow-rate in liters per minute here.Fluid: here you can pick the type of fluid in your pipe.Ĭurrently the following fluids are available (more can be added on demand):.Fluid temperature: enter the average fluid temperature here.Pipe length: enter the relevant length of your pipe.Pipe diameter: enter the inner diameter of the pipe.You will only have to specify the desired input parameters. heating-pipes, cooling-pipes, ventilation pipes, chimneys, heat-exchanges, boilers, condensers, evaporators, cold-water pipes, hot-water pipes, refrigerator pipes, engine pipes,… This can be relevant for many applications, e.g. The tool is very powerful if you attempt to calculate the heat-loss (or gain) of pipes containing a flowing medium.

Fluid dynamics calculator