Highly Sensitive Hot-Wire Anemometry Based on Macro-Sized Double-Walled Carbon Nanotube Strands
Dingqu Wang,
Wei Xiong,
Zhaoying Zhou,
Rong Zhu,
Xing Yang,
Weihua Li,
Yueyuan Jiang,
Yajun Zhang
Affiliations
Dingqu Wang
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
Wei Xiong
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
Zhaoying Zhou
State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
Rong Zhu
State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
Xing Yang
State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
Weihua Li
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
Yueyuan Jiang
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
Yajun Zhang
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
This paper presents a highly sensitive flow-rate sensor with carbon nanotubes (CNTs) as sensing elements. The sensor uses micro-size centimeters long double-walled CNT (DWCNT) strands as hot-wires to sense fluid velocity. In the theoretical analysis, the sensitivity of the sensor is demonstrated to be positively related to the ratio of its surface. We assemble the flow sensor by suspending the DWCNT strand directly on two tungsten prongs and dripping a small amount of silver glue onto each contact between the DWCNT and the prongs. The DWCNT exhibits a positive TCR of 1980 ppm/K. The self-heating effect on the DWCNT was observed while constant current was applied between the two prongs. This sensor can evidently respond to flow rate, and requires only several milliwatts to operate. We have, thus far, demonstrated that the CNT-based flow sensor has better sensitivity than the Pt-coated DWCNT sensor.
