Design and optimization of multivariable controller for CSTR system

Sensors and Actuators A: Physical

Phan

et al. 2018

Thermoresistive properties of a Cubic Silicon carbide (3C-SiC) on glass sensor are studied. The negative temperature coefficient leads to an increasing signal with increasing flow velocity.  The relationship between the geometry of the SiC heater and the sensor performance is studied. A larger heater leads to a higher sensitivity.  Influence of flow direction on the sensor performance was studied. Downstream sensor is more sensitive.  The developed SiC thermal flow sensor combines the advantages of simplicity, low power consumption, high sensitivity and full dynamic range of air flow.

Section: Accepted Manuscriptmentioning

confidence: 99%

Highly sensitive 3C-SiC on glass based thermal flow sensor realized using MEMS technology

Sensors and Actuators A: Physical

Phan

et al. 2018

“…[14][15][16] On the other hand, platinum 17 , diamond 18 Low-temperature cofired ceramics (LTCC) 19 , stainless steel 20 , yttriazirconia 21 and silicon compatible materials 22,23 were a few used for temperature and flow sensing applications. The application fields with these environments include aerospace 24 , automotive 25 , industrial process control 26 and sea exploration 27 . For instance, measuring flow velocity and flow rate in harsh environments is critically important in automotive industry because of the presence of high temperature, corrosives and particulates.…”

Section: Introductionmentioning

confidence: 99%

A hot-film air flow sensor for elevated temperatures

Review of Scientific Instruments

Nguyen

et al. 2019

We report for a novel packaging and experimental technique to characterize thermal flow sensors at high temperatures. To start with, the paper briefly presents the fabrication of 3C-SiC (silicon carbide) on a glass substrate via anodic bonding, followed by the study of thermoresistive and Joule heating effects in the 3C-SiC nano-thin film heater. A high thermal coefficient of resistance (TCR) of approximately-20,720 ppm/K at ambient temperature and-9,287 ppm/K at 200°C suggest the potential use of silicon carbide for thermal sensing applications in harsh environments. During the Joule heating test, a high temperature epoxy and a brass metal sheet were utilized to establish the electric conduction between the metal electrodes and the SiC heater inside a temperature oven. In addition, the metal wires from the sensor to external circuitry were protected by a fibre glass insulating sheath to avoid short-circuit. The Joule heating test ensured the mechanical and Ohmic contact stabilities at elevated temperatures. Using a hot-wire anemometer as reference flow sensor, calibration test was performed at 25°C, 35°C and 45°C in the oven. Finally, the SiC hot-film sensor was characterized for a range of low air flow velocity, indicating a sensitivity of 5 mm-1 s. The air flow was established by driving a metal propeller connected to a DC motor and controlled by a microcontroller. The materials, metallization and interconnects used in our flow sensor were robust and survived temperatures of around 200°C.

“…Figure 1 a represents various MEMS sensors and the associated harsh environment conditions. These conditions are typically found in combustion optimization and emission control, oil industries, chemical process control, the propulsion systems of spacecraft and deep-sea devices [ 2 , 3 ]. In recent years, a number of flow sensors have been fabricated and characterized for the measurement of pressure [ 4 , 5 , 6 ], temperature [ 7 , 8 ], gas species [ 9 , 10 , 11 , 12 , 13 ], strain [ 14 , 15 , 16 , 17 ] and acceleration [ 18 , 19 ] in these environments.…”

Section: Introductionmentioning

confidence: 99%

Thermal Flow Sensors for Harsh Environments

Phan

et al. 2017

Sensors

Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application.