AN ALTERNATE METHOD TO PREVENT SAND ABRASIVE EROSION IN PIPELINES FOR TRANSPORTING HIGH-SPEED NATURAL GAS

This paper presents an alternate method to remove the sand carried by natural gas in the upstream pipelines therefore preventing sand abrasive erosion in pipelines used in transporting high speed natural gas. Conventionally, most experts pay much attention to improving the anti erosion characteristics of the pipeline materials to solve the problem of serious abrasive erosion, but without significant success. Based on the theory of multiphase flow and analysis of the characteristics of sandy jets, a new equipment named 'Sand Catcher' is introduced in this article. Experimental results show that the Sand Catcher effectively removes most of the sand in the natural gas and significantly reduces the abrasive erosion of the pipelines. The Sand Catcher can be widely applied in practice in the near future.

Experimental Investigation on Constrained Abrasive Fluid Polishing for Optical Glass

To find a cost effective,high-precision and environmental friendly way of polishing for optical glass,a series of experiments were focused on about constrained abrasive fluid polishing. Since abrasive particles can repeatedly impact the workpiece in a multidirectional way with high energy, the constrained abrasive fluid polishing method for optical glass has been proposed based on the abrasive fluid machining theory and elastic emission machining theory. A constrained abrasive fluid polishing system was designed and developed to polish K9 glass samples. Results show that K9 glass obtains a high accuracy with less fluid. Experiments indicate that,in a more effective,high-precision and environmental friendly way,constrained abrasive fluid polishing is possible to improve the quality of workpiece surface compared with free abrasive fluid polishing. In the process of removing materials of constrained abrasive fluid polishing,it gives priority to removing the materials of high spot and the high frequency error of smooth local zone can be modified. The abrasive particles can repeatedly impact the workpiece in a multidirectional way,and there are certain relationship among surface quality,material removal rate, and parameters such as speed,clearance, angle, time and particle size. In the process of constrained abrasive fluid polishing, it shows a high material removal rate,and it needn't to clamp workpieces. As a result,it could improve the processing efficiency significantly. The research on constrained abrasive fluid polishing has a practical significance and practical value in industrial production.

Research on Prediction Model for Erosion and Abrasion of Barrel Based on LSSVM

To predict the erosion and abrasion of high bore pressure tank gun barrel, the least square support vector machine (LSSVM) algorithm was used. Based on the gun firing test data, the prediction model for barrel's erosion and abrasion was established. It was adopted to predict the wear increment of gun barrel. The results show that the prediction values given by the model coincide with the measured data better, and the model can predict the barrel's wear accurately and rapidly.

MECHANISM AND PREDICTION OF MATERIAL ABRASION IN HIGH-VELOCITY SEDIMENT-LADEN FLOW

The wall surface of material is prone to silt abrasion by high-velocity sediment-laden flow. The silt abrasion is different form cavitation erosion. In this article, the characteristics of silt abrasion were discussed, The mechanism of silt abrasion was analyzed and the formation and development of ripple shape on wall surface of material were explained thereafter. Based on turbulence theory and test data, some formulas were derived for predicting the abrasion rate of concrete wall surface in high-velocity sediment-laden flow. The calculated results show good agreement with the experimental data.