Abstract
Temperature rise and elastic deformation are unavoidable issues occurring in high-speed gas microbearings due to the dominant small-scale fluid dynamics in rarefied gas flow applications. In this paper, thermo-elasto-aerodynamic analysis requires simultaneously solving the modified Reynolds equation, modified energy equation, temperature–viscosity relationship and the elasticity equations for predicting the lubrication characteristics of microbearings. A thermo-elasto-aerodynamic lubrication is systematically investigated by using the partial derivative method, finite difference formulation and the finite element approach. The results indicate that, compared with rigid microbearing which has a constant viscosity gas lubricant, the temperature effect increases the load capacity, friction coefficient and stiffness coefficients, and it decreases the attitude angle and damping coefficients of the microbearing. The flexibility of the bearing pad also leads to the increase in load capacity and direct stiffness coefficients, while it remains to further decrease the direct damping coefficients on the basis of thermo-aerodynamic performance. The present study is conducive to accurately analyze the microscopic flow properties in a microbearing-rotor system.
Highlights
Along with the rapid development of microfabrication technologies, high-speed gas-lubricated microbearings are one of the vital components in various rotating microdevices and power micro-electro-mechanical system (MEMS) applications such as microturbines, microgenerators, microdrills, micropumps and magnetic storage products
In the condition of considering the temperature–viscosity effect of rarefied gas and the flexibility of bearing pads, this paper investigates the static and dynamic characteristics of gas-lubricated journal microbearings, including the temperature distribution of gas film, load capacity, attitude angle, friction coefficient and dynamic coefficients of bearing for various parameters
The modified Reynolds equation is solved using the relaxation iterative scheme and partial derivative method, and the finite element approach is utilized to compute the elastic distortions induced by the aerodynamic pressure
Summary
Along with the rapid development of microfabrication technologies, high-speed gas-lubricated microbearings are one of the vital components in various rotating microdevices and power micro-electro-mechanical system (MEMS) applications such as microturbines, microgenerators, microdrills, micropumps and magnetic storage products. They can offer certain advantages over conventional oil film bearings, rolling element bearings and active magnetic bearings in a microsystem [1,2,3]. In order to guarantee the safe and reliable operating conditions of microfluidic machines, it is desirable to reveal the interactions between gas compressibility, rarefaction, temperature rise and the bearing flexibility on rarefied gas flow
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