Study On Dynamics Of Standard Measurement Gear Of High Temperature Rotational Speed Calibration Device

Nowadays,achieving calibration of electromagnetic sensors of rotational speed in high-temperature environments is a challenge.The standard measurement gear of the high temperature rotational speed calibration device faces the challenges of high temperature,high speed and narrow flow fields during operation.The mechanism of the effect of the complex operating conditions on the modalities and the windage power losses of the gear is unclear so there are safety hazards.Therefore,this dissertation uses numerical simulation methods to study the modal changes under centrifugal loads,aerodynamic loads,thermal loads alone and coupling for standard measurement gear structures,and to analyze the influence of different loads on the main modes of the gear.Study of the influence of different structural parameters(gear radius,number of teeth and gear thickness)on the main modes of the gear on the basis of coupled loads.And then,the effect of multi-parameter(gear radius,number of teeth,gear thickness,rotational speed)on the windage power loss of the gear is studied to provide a basis for the selection of gear and optimization of windage in practical applications.The dissertation is divided into the following aspects:(1)A finite element model based on the hot-air type high temperature rotational speed calibration device has been developed,the modal order is selected according to the effective mass of the modal,and the effect of centrifugal load on the modes of the gear is investigated,and the main modes studied in this dissertation is determined.Then the stresses that caused by aerodynamic loads in the gear with and without high temperature bins are calculated and compared to obtain the effect of the narrow flow field on the aerodynamic stresses and the effect of the aerodynamic stresses on the modalities of the gear.(2)On the basis of a narrow flow field,injecting high temperature gas and comparing the changes before and after the injection of the temperature field in the vibration response of the gear by centrifugal and aerodynamic loads.Then,by means of the thermal-fluid-solid coupling method,the variation of the modal frequencies of the main modes of the gear in the presence of thermal loads only is calculated.Finally,the influence law of the three load coupling effects on the modal frequencies of the main modes of the gear is analyzed.(3)To calculate the vibration response of gear with different root radii,tooth numbers and gear thickness parameters under the action of coupling load,and to obtain the influence law of each structural parameter on the mode of gears,so as to provide some reference for the selection of gears.The windage power loss of the gear is calculated under different rotational speed,root radii,tooth numbers and gear thickness parameters,and an empirical formula for calculating the windage power loss of the gear is proposed based on the simulation data to provide a quickly method to estimate the windage power loss of standard measurement gear of high temperature rotational speed calibration device.