| EOR and maintaining production in oil and gas field, fracturing operations is an increasingly important role. Fracturing pump as a key fracturing, acidizing equipment composition, its stability and service life directly affect the progress of fracturing. How to effectively reduce the wear rate of the fracturing fluid end pump plunger seal system has become an urgent problem. Numerous studies have shown that the surface texturing technology has a prominent function in lubrication, wear and noise reduction, etc. Therefore, it has become a hot research field of tribology. How to apply surface texture technical to plunger seal friction surfaces to improve their tribological properties is the main research direction of this thesis.Surface texturing means that creating regularly arranged dot matrix of geometric and dimensions on friction surface of the object by some processing methods. Domestic and international studies have demonstrated that the surface texturing has some functions in capturing abrasive, acting as storage tanks, generating hydrodynamic effects, ect.during friction process. In this paper, the tribological performance changes on surface texturing with different shapes and fixed circular in the unit specimen were explored by MDW-100 vertical universal friction. In addition, thickness of oil film between the plunger and the rubber seal in the actual conditions was calculated by one-dimensional Reynolds equation derivation. Finally, the proper laser ablation process for full size of the plunger surface texturing was designed. And the best surface texturing machining was completed. The study made the following value results:(1) Not all the 20# steels and NBR having surface texture are better than the non-textured in the tribological properties. Surface texturing has the possibility of increased wear. The design parameters of surface texture should take small pit, low area ratio when elastomer was involved in friction pair. For the depression in high contact stress can increase the friction.(2) The tests were carried out in fixed speed 928r/min, the test length 3600s, media lubrication L-CKD150. The results showed:when the friction is the ring/ring, the optimal performance of specimen tests is the surface texturing of area ratio 5%, pit depth 40?m among 14 sets parameters of uniform arranged circular. Compared to the non-textured, it is 42.0% lower wear of piston specimen and a minor abrasion. When the friction is the pin/ring, the optimal performance of specimen tests is the surface texture of area ratio 2%, pit depth 40?m, uniform arranged in 20 sets of circular parameters. Compared to the non-textured, the average coefficient of friction is lower 56.2% and the temperature rises 55.4%, the surface worn direction uniform.(3) Calculate the actual conditions oil film thickness is 0.96?m of plunger seal friction, thereby determining the friction state between the boundary lubrication and mixed lubrication. The preferred texture single concave pits around the pressure distribution simulation analysis results:lubricating oil flows through the surface texture after the oil film pressure will rise.(4) Designed a laser ablation process can make surface texturing on the cylindrical surface, the realization of full size plunger textured using the process, and achieved the anticipated effect.In summary, this study innovatively applied the surface texturing technology to fracturing pump plunger surface. Through experiment and theoretical analysis of the surface texturing that can greatly enhance the tribological properties, providing a new idea to further improve lubrication performance and enhanced wear resistance of the seal pair. |
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