According to the problem of dynamic calibration of the thermocouple, especially impossible to evaluate the rise time and to unify the calibration method, a new method of thermocouple calibration is proposed. Based on the method rise time of the input signal of thermocouple and step amplitude could evaluate accurately. The practical process of calibration shows that the method is effective.

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Various environmental factors will adversely influence accelerometers working in the field. Mixed inputs, including external causes and the intended acceleration, are important contributors to the problem. As a consequence, calibrating accelerometers with multiple accelerations is required by manufacturers and customers. We introduce a multi-component mechanical system called vibrafuge to provide multiple accelerations. In this paper, we deduce a general model of the accelerations reproduced by an ideal vibrafuge with homogeneous transformation of matrix. Based on the model, we have an elementary analysis of the components of the output acceleration and point out two byproducts. Investigation in this paper could lay the groundwork for vibrafuge testing of accelerometers.

Traditional heat-exchanger can ensure the air in chamber a specific bulk temperature, but cannot guarantee the temperature distribution is even. A heat exchanger and temperature homogenization device was designed to precisely adjust the temperature and temperature uniformity of airflow. The device was made up of several parallel processing units. Each unit was an independent heat exchanger with temperature homogenization function. To improve the design of the device, evaluation indexes were proposed for both heat transfer capability and temperature uniformity of the airflow field. Analysis and comparison of 3D numerical simulations using FLUENT were made to figure out the optimal way. The model proposed can provide guidance for practical applications. The final results indicate field synergy principle can be used to analyze the temperature homogenization of airflow.

Abstract. In order to research the transient-state flow field characteristics of spherical spiral groove aerodynamic bearings, the bearing's 3D micro gas film mathematical model was established, and analyzed the 3D gas film pressure field of the bearing based on the FLUENT software of fluid dynamics, and obtained the bearing structure parameters and operation parameters of the maximum bearing load capacity. Based on the maximum bearing capacity, the effects of different speeds and eccentricity ratio on dynamic characteristic coefficients were studied, and to explore the gas bearing's transient nonlinear dynamic behavior. The axis orbit of the bearing in different speeds is simulated and the stability of bearing is researched. The results show that based on the maximum bearing capacity, a reasonable choice of the bearing speed and eccentricity contributes to improve the dynamic characteristics, and the stability of rotor-bearing system. The paper provides a theoretical prediction to improve the stability of gas bearing in complex environment.