Calibration-Free Volume Flow Measurement Principle Based on Thermal Time-of-Flight (TToF)

Abstract

For measurement problems with unknown fluids a new calibration-free volume flow measurement technique is developed. This measurement technique includes a discontinuous heat source associated with a minimum of two thermal sensors arranged downstream. The heat source is used to generate a signal code [dT/dt] by injection of local thermal pulses into the flow line. The thermal sensors detect the time-dependent thermal gradients in the fluid at different positions. Herewith, the measurement technique aims at the determination of the flow velocity by ToF, with the particular advantage of applying to measurements of any fluids with unknown properties. The volume flow is determined by integrating the flow profile.