Bent pipe with inner spiral fins on near wall surface

Abstract

The invention aims to provide a bent pipe with inner spiral fins on a near wall surface, is suitable for the field of conveying of gas-liquid two-phase fluids and fluids containing volatile mediums, and aims to eliminate boundary layer separation and secondary eddy currents caused by change of the flowing reverse direction of the bent pipe and non-cooperation of inner and outer side curvatures ofthe pipe wall surface, so that the corrosion degree of the inner and outer wall surfaces of the bent pipe is reduced, and the service life of a fluid conveying pipe is prolonged. The bent pipe with the inner spiral fins on the near wall surface comprises a bent pipe body, an inlet pipe port flange and an outlet pipe port flange at two ends of the bent pipe body, and 2-6 sets of inner spiral fins;the inner spiral fins extend from an inlet to an outlet in the bent pipe along the inner wall surface of the bent pipe body; the inner spiral fins are variable-pitch fins; and the pitch is gradually reduced and then increased in the flowing direction.

Description

technical field [0001] The invention belongs to the technical field of pipeline anticorrosion, and in particular relates to an elbow with internal spiral fins on the near wall surface of a fluid delivery pipeline for realizing corrosion reduction. Background technique [0002] Pipelines are the key equipment for the oil refining and chemical industry to realize fluid transportation, connect various processes, and ensure the normal operation of the process; in the process of oil refining and chemical production, there are many types of fluids transported by pipelines, which can be divided into pure gas phase, pure Liquid phase, gas-liquid two-phase and gas-solid two-phase. At present, when transporting gas-liquid two-phase or pure liquid phase fluid containing volatile components, the fluid flows through the position of the pipe elbow. Due to the incoordination of the inner and outer curvatures of the pipe elbow, the fluid is on the inner and outer walls of the elbow. In par...

AI Technical Summary

Problems solved by technology

At present, when transporting gas-liquid two-phase or pure liquid phase fluid containing volatile components, the fluid flows through the position of the pipe elbow. Due to the incoordination of the inner and outer curvatures of the pipe elbow, the fluid is on the inner and outer walls of the elbow. In particular, boundary layer separation occurs on the inner wall near the outlet, and secondary eddy currents are generated due to the uneven pressure on the inner and outer walls. These two phenomena lead to serious cavitation corrosion on the inner wall of the elbow near the outlet; therefore It is of great significance to improve the corrosion characteristics of the elbow and to increase the life of the pipe.

[0003] There are many measures to reduce pipeline corrosion, including adding corrosion inhibitors, coating protection, changing pipeline materials, and cathodic protection. It is proposed that it has little effect on reducing the corrosion caused by boundary layer separation and secondary vortex caused by the reverse flow change of the elbow and the incoordination of the inner and outer curvature of the pipe wall; the existing literature (patent number: ZL201410155224.X) Also proposed a pipeline damping device to reduce vibration and cavitation, which mainly uses a set of spiral guide tubes with variable lift angles and double-sided spiral guide tubes with variable lift angles to generate swirling flow to reduce pipeline vibration and eliminate cavitation, but the structure of this pipeline damping device is relatively complicated, and it is not suitable for the elbow structure. However, the existing documents (patent number: ZL201710392415.1, patent number: ZL201520040984.6) respectively propose a The inlet fluid spiral guide energy-saving device, the compressor exhaust pipe that relies on the spiral guide part to improve the oil-gas separation efficiency, and the compressor with this exhaust pipe, but the flow resistance loss of these two devices is relatively large, and they do not have Variable cross-section diversion

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