Design Optimization Analysis of Venturi Tube for Medium Conveying in Strengthen Grinding Process

Venturi tubes are widely used in manufacture and chemical industry and attract broad attention. To improve the transmission efficiency, the optimization of Venturi tube has been carried out, the transport substances involved in either liquid, solid, gas or two of them. The Venturi tubes that used for conveying of three-phase flow, which is consisted of solid, liquid and gas, are poorly investigated. In this paper, a Venturi tube employed in one surface treatment equipment was proposed. The velocity and pressure distribution in the flow field of Venturi tube with different key geometric parameters including diameter ratio, convergence angle and diffuser angle have been studied. One optimal solution has been selected. The negative pressure of suction port can reach a value as high as -1550 Pa to -1600 Pa. Such negative pressure offers the opportunities for transporting mixed abrasive.

Preparation and Properties of the Composite Enhancement Layer of Bearing Ring

In this paper, the NU308 bearing rings were subjected to strengthen grinding treatment (SGT) at ambient temperature. And the running reliabilities of specimens that subjected to SGT and conventional treatment (CT) were respectively investigated by testing dynamic properties including the running temperature, vibrations, and surface burning. Moreover, the residual stress, microtopography, and microstructures on the cross-section were respectively tested with residual stress analyzer and field-emission scanning electron microscopy. The results showed that the running reliabilities of the specimen after SGT had been significantly improved with the reduction of running temperature, vibration, and surface burning. Further study showed that the specimen’s surface was filled with disordered micropores after SGT compared to the regular strip texture on the CT specimen’s surface, and the maximum residual compressive stress induced by SGT was about −900 MPa. Moreover, the thickness of the residual compressive stress layer was over 180 µm, while the thickness of severe plastic deformation layer was about 50 µm.

Review of conceptual and systematic progress of precision irrigation

Precision irrigation,defined as accurate and appropriate agricultural techniques characterized by optimal management and best collaboration of various irrigation factors,attracts great attention and obtains wide employments in different irrigation conditions or cultivation processes.Moreover,it becomes well-established in major areas of agricultural researches and across the broad spectrum of agricultural techniques especially in specific sectors of scientific frontiers,including soil quality,irrigation scheduling,water resource distribution,crop productivity,tillage management,climate adaptation,and environment monitoring,etc.This paper reviews the research developments and integrated applications of precision irrigation in typical domains of mechanism and performance,covering key aspects such as process optimization,schedule modelling,and effectiveness evaluation,indicating that advanced irrigation optimization methods support higher productivity of crop field and better environmental conditions of soil;Current schedule modelling techniques provide a set of instructive demonstrations and heuristic descriptions for the working principles of precision irrigation and the quantitative assessments of irrigation productivity;The novel investigation on effectiveness evaluation is extremely significant to obtain higher infiltration efficiency,simultaneously to achieve the optimized irrigation qualities for water balance condition,soil water redistribution,and soil moisture uniformity so that the effectiveness quality of irrigation infiltration could be improved remarkably.It is concluded that precision irrigation owns an outstanding collaborating capability and possesses much better working advancement in typical calibration indexes of cultivation accuracy and infiltration efficiency,meanwhile,a high agreement between the predicted and actual irrigation effectiveness could be expected.This novel irrigation review concentrating on the conceptual and systematic progress should be promoted constructively to improve the quality uniformity for precision irrigation and its constructive influences in different applications,and to facilitate the integrated management of agricultural production by higher irrigation efficiency consequently.