Optimization of micro Knudsen gas sensor for high precision detection of SO2 in natural gas

Impact of Improved Design on Knudsen Force for Micro Gas Sensor

“…The variation of the shuttle arm configuration did not affect the flow patterns of the thermal stress flow (flows A, D1, and D2) and thermal edge flow (flows E1, E2, and E3) near the sharp edges of the heater arm. These similar flow patterns have also been observed in previous research [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…However, in designs 1 and 2, the gas temperatures over the bottom surfaces decreased gradually from left to right, thus thermal stress slip flow F was induced [ 48 ], flowing from the high temperature region to low temperature region, as shown in Figure 3 b,c. The strength of the gas flows above varied due to different pressures and gas species [ 2 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 43 , 44 ]. Additionally, the mass concentration of the gas was considered in the gas mixture [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…DSMC is a highly-efficient method to solve the Boltzmann equation [ 40 , 41 ]. Moreover, the DSMC method has been widely used in the research of rarefied gas flow induced by temperature field [ 42 , 43 , 44 ] and low-pressure gas actuators based on Knudsen force [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ].…”

“…In order to analyze how the working condition and geometric parameter help to improve MIKRA performance, Gerdroodbary et al [ 26 ] found that the peak value of Knudsen force will increase more than seven times if the temperature difference between the shuttle and heater arms is increased from 10 K to 100 K. Moreover, through increasing the arm height and height-to-thickness ratio, they found that [ 27 ]: (i) the Knudsen force has a peak value enhancement of about 3.66 times by increasing the arm height to three times; and (ii) the peak value of the Knudsen force will increase about 5.33 times if the height-to-thickness ratio is increased nine times. Recently, Zheng et al [ 34 ] also demonstrated that the increase in arm height could improve the Knudsen force by applying response surface methodology (RSM). Meanwhile, they pointed out that both an increasing arm gap and decreasing operating pressure could help to improve Knudsen force.…”

“…On the other hand, within an ambient pressure of 25 Pa to 1500 Pa, MIKRA can achieve the detection of gases (N 2 –H 2 O, Kr–Xe, He–Ne–Ar, N 2 –H 2 , CH 4 –SO 2 , CO 2 , N 2 –NH 3 , and Air–H 2 ) [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Knudsen force is linearly dependent on the concentration of any gas species in a gas mixture [ 36 ].…”