Experimental Research On Temperature Rise Control Of Large Geotechnical Centrifuge

Geotechnical centrifuge is the most advanced and effective test platform for studying geological performance and geotechnical structure.As the test conditions required for geotechnical tests become more stringent,the requirements for the scale of the centrifuge,such as capacity and acceleration,are increasing.The heat production of geotechnical centrifuges is also increasing.If the heat production i5 not dissipated in a timely manner through effective temperature-controlled heat dissipation technology,the heat will accumulate in the centrifuge chamber,causing the temperature to rise and causing damage to the instrument.The design of large geotechnical centrifuge must be accompanied by the design of its temperature control system.By studying the heat generation and heat dissipation mechanism of large geotechnical centrifuge,the corresponding temperature control plan should be formulated.The purpose of this paper is to conduct a temperature control test study under atmospheric pressure geotechnical centrifuge and low vacuum high speed centrifuge through a combination of theory and experiment,to explore the heat production mechanism of high speed rotor,analyze the heat dissipation mode,and explore the low vacuum Temperature control effect of geotechnical centrifuge.Provide test data and design method of temperature control system for the construction and landing of 1500g large high-speed geotechnical centrifuge.The basic content of the paper is as follows:(1)A brief introduction to the development history of large geotechnical centrifuges at home and abroad,summarizing the representative geotechnical centrifuges in China,and introducing the related experimental research of geotechnical centrifuges.Secondly,it analyzes the heat generation mechanism of the geotechnical centrifuge,summarizes the domestic and foreign articles related to the heat generation of the centrifuge,and finally introduces the main cooling methods and related research of the geotechnical centrifuge,including air cooling system and water cooling system.(2)The derivation process of the wind resistance power calculation model is introduced,the mainstream calculation formulas are analyzed and compared,and the wind resistance power calculation formula suitable for the 1500g large geotechnical centrifuge is selected.The mechanism of wind resistance power is further subdivided,the first and second heat source theory is proposed,the heat generated by the relative movement of the arm and the air is regarded as the first heat source,and the heat generated by the friction between the flowing air and the wall surface is regarded as the second heat source.The basic form of heat transfer in the centrifuge room is introduced,and the theoretical analysis of the heat transfer process is carried out.(3)Develop a temperature control test plan for the ZJU400 large-scale geocentrifuge,conduct tests in the three seasons of spring,summer and winter,measure the temperature distribution in the machine room and the heat dissipation of the air-cooled water cooling system,and determine the respective heat of the two heat sources in the machine room through the temperature distribution For the direction of transfer,the heat transfer between the wall and the air is calculated using the circular tube heat transfer model to determine the specific heat output of the first heat source and the second heat soiurce and the proportional relationship between them.It provides a test basis for the heat generation calculation of specific parts of 1500g high-speed geotechnical centrifuge.(4)In order to study the heat generation mechanism of geotechnical centrifuge under vacuum environment,a vacuum high-speed centrifugal test system was designed in equal proportion.By measuring the temperature rise of the centrifuge room under different vacuum degrees,the temperature control effect of the vacuum degree on the centrifuge is investigated,and the wind resistance power under each vacuum degree is calculated to determine the corresponding relationship between the wind resistance power and the vacuum degree.Finally,the side wall liquid cooling temperature control method is added to investigate the vacuum conditions that can maintain the stable temperature of the centrifuge room within the allowable range of normal work.Provide an effective temperature control scheme for the design of large geotechnical centrifuges.