Dynamic and Static Characteristics Analysis Study of Hot-Wire Probe in Constant Temperature Model

Abstract

Lumped and distributed dynamic/static models of constant temperature hot-wire probe are established according to heat balance principle. Dynamic and static characteristics of hot-wire probe are analyzed in terms of hot-wire probe sizes, control circuit parameters and flow velocity.Simulation results show that reliability and stability of the hot-wire probe depend on bias voltage.The dynamic and static characteristics of hot-wire probe refly on the ratio of length to diameter ratio crucially.Once the ratio exceeds 300, heat conduction terminal loss can be ignored. When over-heating ratio of hot- wire or flow velocity increases, heat conduction terminal loss can be omitted as well .Besides frequency response of hot-wire probe can be improved simultaneously.The above conclusions can provide guidance in the improved design for hot-wire probe and its control-circuits.