The quality of crushing,power consumption,and discharging performance of a straw crusher are greatly influenced by the characteristics of its internalflowfield.To enhance the straw crusher’sflowfield properties and improv...The quality of crushing,power consumption,and discharging performance of a straw crusher are greatly influenced by the characteristics of its internalflowfield.To enhance the straw crusher’sflowfield properties and improve the efficiency with which crushed material is discharged,first,the main structural parameters influencing the airflow in the crusher are discussed.Then,the coupled gas-solidflowfield in the straw crusher is numerically calculated through solution of the Navier-Stokes equations and application of the discrete element method(DEM).Finally,the discharge performance index of the crusher is examined through detailed analysis of the crushed material dynamics.Additionally,a multi-island genetic algorithm is used to optimize the structure and operational factors that have significant effects on the discharge performance.With optimization,the accumulation rate of crushed materials in the bottom region of the straw crusher decreases by 20.08%,and the massflow rate at the discharge outlet increases by 11.63%.展开更多
All vessels and offshore units require regular inspections to prevent structural or functional damages. Periodical inspections are based on classification society＇s requirements and include both visual surveys and no...All vessels and offshore units require regular inspections to prevent structural or functional damages. Periodical inspections are based on classification society＇s requirements and include both visual surveys and non-destructive test interventions, to look for structural damage, pitting, corrosion, thickness measurement, usually documented by measurements or images. Different approaches of inspection can be proposed for underwater and for dry areas, using unmanned vehicles or service robots able to improve traditional inspection methods. Several excellent proposals are today available： nevertheless, reasons of costs, operation complexity and impossibility to cover all types of inspection with a unique autonomous unit limit and conditions the applicability of automatic inspection systems. The paper is the first of a series describing the main results of a wide research activity carried out at DREAMS Lab （Laboratory of Drives and Experimental Automation for Marine Systems） of the University of Genoa. The studies are oriented to the realization of a kit of low cost and unsophisticated self-moving units, devoted to support some recursive inspections in dry areas of ships and on offshore plants as bulkheads, holds, double bottoms and ducts. The paper describes the design and prototyping of a pneumatronic unit oriented to inspection and maintenance of ship holds. Conceived to realize a portable and user-friendly tool which could take part of an ＂inspection kit＂ for the use of inspectors, able to simplify and speed up the inspection visits with and automatic generation of survey reports.展开更多
基金supported by Basic scientific research funding project of universities directly under the Inner Mongolia Autonomous Region(Grant No.JY20230077)the Natural Science Foundation of Inner Mongolia Funded Project(Grant No.2022FX01)+1 种基金Inner Mongolia Nature Joint Science Fund(Grant No.2023LHMS05023)Qiqihar University Educational Science Research Project(Grant No.GJQTYB202320).
文摘The quality of crushing,power consumption,and discharging performance of a straw crusher are greatly influenced by the characteristics of its internalflowfield.To enhance the straw crusher’sflowfield properties and improve the efficiency with which crushed material is discharged,first,the main structural parameters influencing the airflow in the crusher are discussed.Then,the coupled gas-solidflowfield in the straw crusher is numerically calculated through solution of the Navier-Stokes equations and application of the discrete element method(DEM).Finally,the discharge performance index of the crusher is examined through detailed analysis of the crushed material dynamics.Additionally,a multi-island genetic algorithm is used to optimize the structure and operational factors that have significant effects on the discharge performance.With optimization,the accumulation rate of crushed materials in the bottom region of the straw crusher decreases by 20.08%,and the massflow rate at the discharge outlet increases by 11.63%.
文摘All vessels and offshore units require regular inspections to prevent structural or functional damages. Periodical inspections are based on classification society＇s requirements and include both visual surveys and non-destructive test interventions, to look for structural damage, pitting, corrosion, thickness measurement, usually documented by measurements or images. Different approaches of inspection can be proposed for underwater and for dry areas, using unmanned vehicles or service robots able to improve traditional inspection methods. Several excellent proposals are today available： nevertheless, reasons of costs, operation complexity and impossibility to cover all types of inspection with a unique autonomous unit limit and conditions the applicability of automatic inspection systems. The paper is the first of a series describing the main results of a wide research activity carried out at DREAMS Lab （Laboratory of Drives and Experimental Automation for Marine Systems） of the University of Genoa. The studies are oriented to the realization of a kit of low cost and unsophisticated self-moving units, devoted to support some recursive inspections in dry areas of ships and on offshore plants as bulkheads, holds, double bottoms and ducts. The paper describes the design and prototyping of a pneumatronic unit oriented to inspection and maintenance of ship holds. Conceived to realize a portable and user-friendly tool which could take part of an ＂inspection kit＂ for the use of inspectors, able to simplify and speed up the inspection visits with and automatic generation of survey reports.
