Torsional Vibration Analysis And Optimization Of Shaft System For Fracturing Pump Truck

In the work process of fracturing pump truck which is equipped by HHP diesel engine, the existing problems are early failure of the crankshaft and high level gear noise of the rear geartrain, and the high torsional vibration level within the shaft system is one of the key factors. Study on the torsional vibration of the shaft system for the HHP fracturing pump truck is less, and the references about the internal combustion engine torsional vibration analysis mostly concentrate on the engine internal excitation only, and the loads of the internal combustion engines are generally regarded as large inertia. But the actual work situation of the fracturing pump truck is very complex, besides the engine itself, the plunger pump's excitation is also one of the excitation source. The plunger pump's working condition is very complex, the instantaneous flow of fracturing fluid itself is not fixed, and the flow rate is fluctuating, so the dynamic incentive that the pump produced is also one of the excitation source of the torsional vibration.Detailed torsional vibration test and simulation calculation of torsional vibration was carried on a fracturing pump track which is equipped by Cummins 60 L high-horse power engine. By combining theory analysis with test measurement, the cause of torsional vibration and the problem induced by torsional vibration was also analysed, and also put forward the well-directed solutions.The root cause of torsional vibration is very complex because of the harsh oil field environment. The study shows that besides the engine internal excitation, the pulse excitation caused by the three cylinder plunger pump is also an excitation source. As for the torsional vibration control, engine internal excitation and plunger pump excitation should be considered synthetically, and dealing well with the complex excitation torque of the internal combustion engine and plunger pump is a key factor in torsional vibration analyzing.The incentive principle of the plunger pump which is the assignable cause of torsional vibration was also analysed, and the relationship between the number of the cylinder of the plunger pump and the flow pulsation, and this work provides an important reference significance for the plunger pump type selection. Finally the principle of the pulsation damper for the fracturing fluid and crankshaft torsional vibration damper were also analysed, and the practical solution that could reduce torsional vibration was introduced, and this work provides a reference for fracturing pump truck torsional vibration optimization.