Signal characterization of a pulsed-wire and heat flow system at a flow sensor

This article describes a pulsed thermal Time-of-Flight (TTOF) flow sensor system as two subsystems i.e., a pulsed-wire system and a heat flow system. The entire flow sensor is regarded system-theoretically as a linear time-invariant (LTI) system and is described by its transfer function or impulse response. The characterization of the thermo-fluid dynamic signals obtained by a pulsed-wire and by a heat flow is strived. Hence, the impulse response of both pulsed-wire and heat flow is analyzed according to the flow velocity. Experimental and theoretical results are compared in a flow velocity range in air between 0.1 m/s and 1.4 m/s.

I. Introduction

Flow meters are widely employed in several industrial, automotive and medical areas primarily for controlling the volumetric or mass pipe flow rates of fluids i.e., gases and liquids, for various purposes. Different flow measurement principles are considered, since the amount of flow of a certain fluid influences many other relevant process parameters such as temperature, level, pressure, chemical composition and dose [1], depending on the fluid characteristics, like viscosity, density, electrical conductivity etc., and the velocity range.