TITLE:
High Precision Bidirectional Heat Pulsed Flow Sensor
AUTHORS:
Jasmin Radadia, Maher E. Rizkalla
KEYWORDS:
Smart Sensor; Temperature; Software; Hardware; High Precision, CFD
JOURNAL NAME:
Journal of Software Engineering and Applications,
Vol.7 No.3,
March
27,
2014
ABSTRACT: In this work we have
designed and simulated a thermal bi-directional integrated circuit mass flow
sensor. The approach used here was an extension to the gas flow model given by
Mayer and Lechner [1]. The design features high precision response received from analog
integrated circuits. An established mathematical model for the heat flow
equation including CFD parameters were used within COMSOL simulation (COMSOL
Multiphysics, Sweden). Heat pulses of 55°C for
a period of nearly 120 seconds and 50% duty cycles were applied as thermal
sources to the flowstream. The boundary conditions of the heat equations at the
solid (heating element) fluid interface were set up in the software for the
thermal response. The hardware design included one heating element and two
sensing elements were used to detect the bi-directional mass flow. Platinum
sensors were used due to their linear characteristics within 0°C to 100°C range, and their high
temperature coefficient (0.00385 Ω/°C). Polyimide thin film heater was used as
the element due to its high throughput and good thermal efficiency. Two bridge
circuits were used to sense the temperature distribution in the vicinity of the
sensing elements.