The gravitational field affects the evolution of multiphase media, such as rocks, soil, and alloy melts. Hypergravity increases the body force of matter, enhancing the driving force of the relative motion between subs...The gravitational field affects the evolution of multiphase media, such as rocks, soil, and alloy melts. Hypergravity increases the body force of matter, enhancing the driving force of the relative motion between substances with different densities and accelerating the evolution of multiphase media. Hypergravity experiments provide a new approach to exploring the motion of multiphase media and solving engineering problems. Hypergravity experiments have been conducted in different disciplines,such as materials science, geological science, and geotechnical engineering. However, the knowledge barriers between various research fields have caused the development of centrifuges/inflight devices and theoretical research on the mechanisms of matter in motion in hypergravity to lag behind the application of hypergravity experiments, limiting the progress in these experiments.This article systematically summarizes and proposes the fundamentals of hypergravity experiments, while the scientific challenge of the nonlinear hypergravity effect induced by high hypergravity on multiphase media evolution is clarified. Evaluation criteria are proposed for the noninertial frame effects of the centrifugal hypergravity field. The development of the high-centrifugal acceleration, large-capacity, and long-beam centrifuges are determined as the future research direction. Representative cases are used to demonstrate the effectiveness and great potential of the hypergravity experiments for the solidification of alloy melts and physical modeling. Challenges in the experimental methodology are also clarified. This paper reviews the fundamentals and applications of hypergravity experiments in various disciplines, pointing out the research direction of hypergravity experiments on multiphase media evolution.展开更多
Temperature rise caused by windage power is a major limitation to the large-scale process of geotechnical centrifuges.However,there is no consensus on how to identify the key parts(parts with high windage power consum...Temperature rise caused by windage power is a major limitation to the large-scale process of geotechnical centrifuges.However,there is no consensus on how to identify the key parts(parts with high windage power consumption)and parameters(the velocity coefficientαand windage coefficient C_(i)),and the influence of idle power is often neglected in methods for calculating windage power.To address these issues,a Centrifugal Hypergravity and Interdisciplinary Experiment Facility(CHIEF)scaled model device was constructed,and the windage power was measured.Then,a computational fluid dynamics(CFD)model of the device was established and validated by experimental results.Simulation results were analyzed to quantify the proportion of the windage power in different parts of the device and summarize the variation law of key parameters.Finally,a novel windage power calculation equation was developed based on the elimination of the influence of the idle power.Results show that the role of the rotating arm cannot be ignored in the selection of key parts.The velocity coefficient and windage coefficient are a function of the device geometry and size,and are independent of the angular velocity.The windage power is proportional to the cube of the angular velocity after eliminating the effect of idle power.展开更多
基金supported by the Basic Science Center Program for Multiphase Media Evolution in Hypergravity of the National Natural Science Foundation of China (Grant No. 51988101)the National Major Scientific and Technological Infrastructure-Centrifugal Hypergravity and Interdisciplinary Experimental Facility (CHIEF)Financial support from the Chinese Program of Introducing Talents of Discipline to University (the 111 Project, Grant No. B18047)。
文摘The gravitational field affects the evolution of multiphase media, such as rocks, soil, and alloy melts. Hypergravity increases the body force of matter, enhancing the driving force of the relative motion between substances with different densities and accelerating the evolution of multiphase media. Hypergravity experiments provide a new approach to exploring the motion of multiphase media and solving engineering problems. Hypergravity experiments have been conducted in different disciplines,such as materials science, geological science, and geotechnical engineering. However, the knowledge barriers between various research fields have caused the development of centrifuges/inflight devices and theoretical research on the mechanisms of matter in motion in hypergravity to lag behind the application of hypergravity experiments, limiting the progress in these experiments.This article systematically summarizes and proposes the fundamentals of hypergravity experiments, while the scientific challenge of the nonlinear hypergravity effect induced by high hypergravity on multiphase media evolution is clarified. Evaluation criteria are proposed for the noninertial frame effects of the centrifugal hypergravity field. The development of the high-centrifugal acceleration, large-capacity, and long-beam centrifuges are determined as the future research direction. Representative cases are used to demonstrate the effectiveness and great potential of the hypergravity experiments for the solidification of alloy melts and physical modeling. Challenges in the experimental methodology are also clarified. This paper reviews the fundamentals and applications of hypergravity experiments in various disciplines, pointing out the research direction of hypergravity experiments on multiphase media evolution.
基金supported by the National Major Science and Technology Infrastructure Project of China(No.2017-000052-73-01-002083)the Information Technology Center,Zhejiang University,China.
文摘Temperature rise caused by windage power is a major limitation to the large-scale process of geotechnical centrifuges.However,there is no consensus on how to identify the key parts(parts with high windage power consumption)and parameters(the velocity coefficientαand windage coefficient C_(i)),and the influence of idle power is often neglected in methods for calculating windage power.To address these issues,a Centrifugal Hypergravity and Interdisciplinary Experiment Facility(CHIEF)scaled model device was constructed,and the windage power was measured.Then,a computational fluid dynamics(CFD)model of the device was established and validated by experimental results.Simulation results were analyzed to quantify the proportion of the windage power in different parts of the device and summarize the variation law of key parameters.Finally,a novel windage power calculation equation was developed based on the elimination of the influence of the idle power.Results show that the role of the rotating arm cannot be ignored in the selection of key parts.The velocity coefficient and windage coefficient are a function of the device geometry and size,and are independent of the angular velocity.The windage power is proportional to the cube of the angular velocity after eliminating the effect of idle power.
