Experimental measurements and numerical simulations of the Knudsen force on a non-uniformly heated beam

Strongrich, Andrew; O’Neill, William; Cofer, Anthony G.; Alexeenko, Alina

doi:10.1016/j.vacuum.2014.05.021

Cited by 22 publications

(11 citation statements)

References 18 publications

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“…Thus, vane configuration plays an important role in improving Knudsen force [ 7 ]. Strongrich et al [ 8 ] analyzed the Knudsen force on a non-uniformly heated cantilever by combining the experimental measurement with numerical simulation. It was found that the Knudsen force is dependent on pressure, geometric shape, and temperature difference.…”

Section: Introductionmentioning

confidence: 99%

Impact of Improved Design on Knudsen Force for Micro Gas Sensor

Wang

Zhang

et al. 2020

Micromachines

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Knudsen force generated by thermally driven gas flow in a microscale structure has been used for gas detection and has shown immeasurable potential in the field of microelectromechanical system (MEMS) gas sensors due to its novel sensing characteristics. In this article, the performances of three kinds of Knudsen force gas sensors with improved isosceles triangular shuttle arm structures were studied. In the first design, the top side and right side lengths were equal; in the second, the top side and bottom side lengths were equal; and for the third, the bottom side and right side lengths were equal. A detailed investigation including gas flow, thermal characteristics, Knudsen force, and coupling effects between the shuttle-heater pairs was conducted using the direct simulation Monte Carlo (DSMC) method and the main mechanisms for gas flow presented were almost the same in this work. However, the second design returned the highest Knudsen force performance. The value increased by 42.9% (P = 387 Pa) compared to the Knudsen force of the original square shuttle arm. The results also demonstrate that the coupling effects become weak toward the right with an increase in the number of shuttle-heater pairs.

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Section: Introductionmentioning

confidence: 99%

Impact of Improved Design on Knudsen Force for Micro Gas Sensor

Wang

Zhang

et al. 2020

Micromachines

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“…One of the effective methods to apply the Knudsen force is to reduce the size of the model and construct micro device [19]. Micro Knudsen gauge and microscale radiometric actuator are the main conventional devices that implement this technique for industrialized applications.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have been directed to inspect and evaluate the key features of Knudsen force in these instruments [18]. Strongrich et al [19] performed experimental work and numerical studies to calculate Knudsen force on a non-uniformly heated beam. They highly focused on this molecular force and finally offer their new micro gas sensor as Micro In-plane Knudsen Radiometric Actuator (MIKRA) as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Application of Knudsen Force for Development of Modern Micro Gas Sensors

Gerdroodbary¹

2020

Gas Sensors

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Development of new simple gas sensor is highly significant due to its various industrial applications. In this chapter, comprehensive studies on the new micro gas sensor of Micro In-plane Knudsen Radiometric Actuator (MIKRA) are done to evaluate the performance of its technique on the detection of gas. This new micro gas sensor works by the radiometric phenomena, which occurs due to temperature difference in rarefied gas. In order to simulate this micro gas sensor, direct simulation Mont Carlo (DSMC) is recognized as a reliable method. This study highly focused on the main mechanisms of the flow feature and force generation in low-pressure domain. In order to study this micro gas sensor, comprehensive numerical results are thoroughly investigated and the effects of primary factors and parameters are revealed. In addition, the main details of computational approach for the simulation of this micro gas sensor are fully presented. Finally, the performance of this sensor in various operating conditions is explained and main findings are discussed.

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“…From a flow modelling viewpoint, Loyalka 41 , using a linearized Boltzmann equation, calculated the longitudinal and transversal Knudsen forces on the cylindrical surfaces of a hanging wire of a vacuum micro-balance. The authors noted Knudsen force maximum in the transitional regime for Helium-an observation attributed to the bimodal nature of radiometric forces 42 In more complex scenarios, one can stack an array of micro-heaters to significantly enhance the Knudsen force output 3,50,51 . Strongrich 51 demonstrated the possibility of amplifying the Knudsen forces as well as reversing its direction by combining thermal gradients between several solid bodies.…”

Section: Introductionmentioning

confidence: 99%

Quantification of thermally-driven flows in microsystems using Boltzmann equation in deterministic and stochastic contexts

et al. 2019

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When the flow is sufficiently rarefied, a temperature gradient, for example, between two walls separated by a few mean free paths, induces a gas flow-an observation attributed to the thermo-stress convection effects at microscale. The dynamics of the overall thermo-stress convection process is governed by the Boltzmann equation-an integro-differential equation describing the evolution of the molecular distribution function in six-dimensional phase space-which models dilute gas behavior at the molecular level to accurately describe a wide range of flow phenomena. Approaches for solving the full Boltzmann equation with general inter-molecular interactions rely on two perspectives: one stochastic in nature often delegated to the direct simulation Monte Carlo (DSMC) method; and the others deterministic by virtue. Among the deterministic approaches, the discontinuous Galerkin fast spectral (DGFS) method has been recently introduced for solving the full Boltzmann equation with general collision kernels, including the variable hard/soft sphere models-necessary for simulating flows involving diffusive transport. In this work, the deterministic DGFS method; Bhatnagar-Gross-Krook (BGK), Ellipsoidal statistical BGK, and Shakhov kinetic models; and the widely-used stochastic DSMC method, are utilized to assess the thermo-stress convection process in MIKRA-Micro In-Plane Knudsen Radiometric Actuator-a microscale compact low-power pressure sensor utilizing the Knudsen forces. BGK model under-predicts the heatflux, shear-stress, and flow speed; S-model over-predicts; whereas ESBGK comes close to the DSMC results. On the other hand, both the statistical/DSMC and deterministic/DGFS methods, segregated in perspectives, yet, yield inextricable results, bespeaking the ingenuity of Graeme Bird who laid down the foundation of practical rarefied gas dynamics for microsystems.

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Experimental measurements and numerical simulations of the Knudsen force on a non-uniformly heated beam

Cited by 22 publications

References 18 publications

Impact of Improved Design on Knudsen Force for Micro Gas Sensor

Impact of Improved Design on Knudsen Force for Micro Gas Sensor

Application of Knudsen Force for Development of Modern Micro Gas Sensors

Quantification of thermally-driven flows in microsystems using Boltzmann equation in deterministic and stochastic contexts

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