This paper researches the evolutions of shock waves in the gas film of aerostatic thrust bearing with a single air supply inlet. The ANSYS Fluent 18.0® is adopted to discuss the flow field characteristics, such as, supersonic flow, negative pressure, load capacity of bearing and backflow area with large values of both gas film thickness and supply pressure. Under thick clearance and large supply pressure conditions, the supersonic flow leads to the appearance of shock wave and causes a negative pressure. If the multi-reflection phenomenon of shock wave occurs, the total load capacity of bearing will even drop to be negative. The above results provide a theoretical basis for people to understand the flow field characteristics of the gas film in the aerostatic thrust bearing under large gas film thickness and large supply pressure conditions, and help the researchers to find out the effective way to restrain the emergence of shock waves and improve the load capacity of aerostatic thrust bearings.

Studies on the evolution of shock wave in gas film clearance for aerostatic thrust bearing

The invention relates to a time calibration system of mobile phone Bluetooth, and relates to the technical field of Bluetooth. The system comprises a mobile phone end and a clock end, the mobile phoneend comprises a processor and a time obtaining module and a time correction unit electrically connected with the processor, the time obtaining module is electrically connected with a wireless networkmodule and a Bluetooth connection module, and the output end of the time correction unit is electrically connected with a signal sending module. The system has the advantages that a clock establishesBluetooth connection with a mobile phone, the mobile phone is connected to the network to obtain standard time and modifies clock time by means of codes, modified time is sent to a clock controller for analysis and conversion, and further a stepping motor controls a clock movement to calibration time; and thus, the clock is calibrated accurately, and time is more accurate.

Time calibration method via mobile phone Bluetooth

The utility model discloses a bluetooth of mobile phone calibrating device of pointer -type clock. The utility model discloses it is main including smart mobile phone, bluetooth module, clock controller module, machine controller module, step motor module and pointer clock. Network standard time that bluetooth of the mobile phone end obtained through bluetooth module send for clock controller, clock controller with network standard time convert into corresponding pulse signal, and fast with pulse signal send for machine controller, machine controller by the analytic time pulse signal of standard time 0, thereby it rotates and drives pointer, the pointer that the steering spindle that links to each other with the pointer of pointer clock drove pointer clock and change to network standard time to drive standard time 3, standard time 3 through standard time 2. The utility model discloses can effectively improve the calibration steps of pointer clock, guarantee the efficiency of calibration, reduce the calibration error among the pointer clock time calibration process, improve the calibration accuracy.

Bluetooth of mobile phone calibrating device of pointer -type clock

Slide stability is key to the aerostatic guide in ultra-precise machines; thus, it has garnered plenty of attention. Macro-scale studies are commonplace, but micro- and nano-vibration issues require more attention. Microscope vibration is mainly caused by tiny changes in the fluid parameters of lubricating gas film, which is complex and has no verdict. In this case, slide-gas interaction should be considered. In this study, the widely used orifice-type restrictor was investigated for its nano-vibration performance. A Comsol finite-element-method fluid–structure interaction model was used to simulate and analyze an orifice-type restrictor, and orifice-restrictor vibration characteristics at the nanometer scale were inspected using a high-performance laser vibrometer. The results demonstrate that see-saw mode vibrations occur in the restrictors, growing stronger with increased air-supply pressure. The see-saw vibration’s axis is speculatively determined based on orifice and restrictor structures, and the vibration type is related to the number of orifices. The results also show that the vibration is random with natural frequencies at the kilohertz level. The newly provided research results are beneficial for better understanding the nano-vibrations of orifice-type restrictors.

Experimental Study of See-Saw Mode Nano-Vibration on Orifice-Type Restrictors

The definition of air resistance is nonuniform when analyzing the bearing capacity, stiffness, and stability of an orifice throttling aerostatic restrictor. In this study, a capillary tube similar to the inlet section of an aerostatic restrictor is used as the research object, and the Bernoulli equation under adiabatic conditions is established. Through an experiment, the pressure and temperature of the capillary tube inlet and outlet and the flow through the capillary tube are measured. Based on the air resistance definition, the empirical formula of the coefficient k is obtained, and the theoretical air resistance of the capillary path is calculated. The relative error between the theoretical air resistance and experimental air resistance is kept within 10%. The comparison results verify the accuracy of the air resistance theory and provide a basis for the subsequent establishment of a universal definition of air resistance. Subsequently, air resistance can be used to design aerostatic bearings and help improve their characteristics.

Characteristics of Air Resistance in Aerostatic Bearings

The invention discloses a Bluetooth calibration method of digital clock The method comprises the steps of after working out the time during which the mobile phone sends network standard time to the calibrated digital clock and the calibrated digital clock receives the network standard time sent from the mobile phone, the invention automatically adds the time during which current network standard time is calibrated and sent to the calibrated digital clock, which effectively reduces calibration error and improves calibration precision In calculation process, multiple groups of data are obtained through determination of the quantity of transfers and total times of continuous measurement of sending network standard time between mobile phone's Bluetooth time calibration end and calibrated digital clock

Jing Yu

Papers

Bluetooth of mobile phone calibrating device of pointer -type clock

Experimental Study of See-Saw Mode Nano-Vibration on Orifice-Type Restrictors

Characteristics of Air Resistance in Aerostatic Bearings

Bluetooth calibration method of digital clock