Published date: Sep 05 2016

Journal Title: KnE Engineering

Issue title: Conference on Science and Engineering for Instrumentation, Environment and Renewable Energy

Pages:

DOI: 10.18502/keg.v1i1.492

Lazuardi Umarlazuardi@unri.ac.id

This paper presents a new model-based approach to detect and compensate errors of positive temperature coefficient (PTC) sensors used for airflow measurement.  From modeling and simulation, it can be shown that the thermal resistance of the sensor at self-heating mode was influenced by air flow magnitude. The sensor of type EPCOS-AG B59010 in a steel case, length 20 mm, diameter 2 mm was characterised over the flow rate range between 0 and 6 m/s and modeled to determine coupling thermal resistance interaction R_th between the medium surrounding and sensor’s structure.  Soiling caused by dust transported with the air on the sensor surface changing in the thermal resistance has observed and simulated in an experiment using a cylindrical sheath of PTFE – Polytetrafluorethylen with known heat conductivity λ_S = 0.24 W/Km and diameter D.  Parameters of model were then calibrated by evaluating current-voltage I(U)-characteristic at air velocity of v = 0m/s, and recalibration is then also used to correct the model parameters for v ¹ 0m/s. Result shows the soiling has exceeded critical thickness at D/d = 9 wherein the thermal resistance tends to be constant meaning cleaning sensor surface or replacing are needed.

[1] C. Jiang, G. Liu, and J. Jiang, A Self-Validating Algorithm for Hot Thermistor Constant Differential Temperature Air Flow Sensor, Proceedings of the 2005 IEEE Conference on Control Applications Toronto, (2005).


[2] P. M. Aleksi, et al., A Thick Film NTC Thermistor Air Flow Sensor, Proceedings of 24th International Conference on Microelectronics (MIEL 2004), (2004).


[3] C. Xu, X. Guo, H. Jiang, Z. Zhang, and S. Liu, Modeling and Simulation of Selfheating Effect with Temperature Difference Air Flow Sensor, 2014 15th International Conference on Electronic Packaging Technology, 655–659, (2014).


[4] M. Horn and L. Umar, Sensorsystem zur Messung der Luftgeschwindigkeit mit automatischer Selbstüberwachung und Selbstkalibrierung, Proceeding of ITG/GMA Fachtagung Sensoren und Meßsysteme 2002, (2002).


[5] L. V. King, On the convective heat transfer from small cylinders in a stream of fluid. Determination of convective constants of small platinium wires with application to hot-wire anemometry, Phil. Trans R. Soc, 214A, 373–432, (1924).


[6] Fenwal, NTC/PTC Thermistor Standard Products Catalog, Fenwal Electronics Inc., Mass., USA (1985).


[7] V. D. I. Wärmeatlas, in VDI-Verlag GmbH, German, Düsseldorf, 1997.