Papers by Author: Zheng Lin Liu

Abstract: The rotary inertia, speed, acceleration of shafting and the friction coefficient of rubber bearings have an important influence on the calculation of shafting resistance moment, related to the selection rationality of driving motor. In order to guarantee load startup and normal operation of the shafting, by analysing shafting rotary inertia, bearing support force and friction coefficient, calculated resistance moment of the shafting, established the mathematical model of shafting equivalent resistance moment and motor rotational speed, compared the output moment of motor with shafting equivalent resistance moment, so that determined the correct motor model.

Abstract: Coupling is mostly used for the connection of two shafts, widely in ship machinery. Because the vibration and impact of propeller under alternating load, the tail shaft work conditions are harsh, pre-tightening force plays an important role in the performance of tail shaft coupling. In this paper, based on conventional coupling, achieve pre-tightening by applying pre-tightening lock bolt at the circumference of pre-tightening nut, determine the pre-tightening force according to empirical formula, analyse the pre-tightening strength by using of Workbench finite element software, get the stress distribution of related parts, to explore the effect of pre-tightening force on the stress of related parts of coupling.

Abstract: Apply FLUENT software to establish the water lubricated rubber stern tube bearing CFD model,study temperature and pressure distribution of the bearings at different speeds of rotation. It plays an important role in improving the performance of ship water lubricated stern tube bearing and security, reliability of propulsion system. The simulation results show that increasing the shaft speed in a certain range can reduce water film temperature, the effect is obvious especially at slow entrance velocity of bearings. Both high and low pressure ranges in the middle of bearings are enlarged with the increase of speed.

Abstract: Spherical stern bearing is kind of new bearing, which combines ordinary water lubricated stern bearing with sphere bearing. It has function to adjust contact situation of stern bearing and stern shaft automatically, decreases pressure peak, leads to pressure distribution on the bearing being more uniform, helps to overcome the problem of local overload to avoid edge effect and improves damping performance. On the base of the ANSYS software, the contact deformation and pressure calculation of spherical stern bearing are carried out to compare with ordinary stern bearing and analyse the effectiveness of reducing pressure on bearing, optimization problems of the sphere position and sphere diameter are discussed, which shows that the contact pressure achieves a minimum when the sphere is located at intermediate position of bearing bush and the maximum contact pressure decreases with the increase of sphere diameter, and they have linear relation.

Abstract: Reasonable assumptions and boundary conditions, the application of CFD method of mechanical seal ring structure analysis and thermal-structural coupling analysis, research on the temperature field and the pressure field distribution of the water flim between moving and the stationary ring . Comparing the change of the maximum temperature and the water film bearing capacity though different inlet velocity and different speed under, known as the fluid inlet speed increases, the maximum temperature of the sealing water film gradually decreased, the bearing capacity gradually increased; as the stern shaft speed increases, the sealing water film maximum temperature gradually reduced, and the bearing capacity of the sealing water film is gradually increased. In this paper, the research to maintain the good performance of the stern shaft mechanical seal has important significance and role.

Abstract: Aeolian vibration often occurs in the high-voltage transmission overhead lines, and the amplitude of conductors has close relationship with conductors fretting wear. It is very difficult to measure actual amplitude of working conductor, so obtaining the amplitude of the conductor by the means of simulation is of practical significant to research quantitatively the relationship of the amplitude and the fretting wear. In this paper an imitation test-bed was built. The maximum amplitudes in the different location of a conductor in a test condition were obtained by Simulink software simulating, and the results were compared with the maximum amplitudes obtained by experimental test. The result of this comparison showed that between of them were of good similarity, and the locations of vibration nodes and maximum amplitudes were basically same. It was proved to be feasible that the aeolian vibration amplitude of the overhead conductor in kinds of conditions could be obtained by Simulink software simulating.

Abstract: In this paper, making ship propulsion shaft as the research object, We do research on characteristics of water-lubricated stern tube bearings and operating performance of ship’s propulsion shaft. Using FEM to discuss the impact law of the geometric properties to water-lubricated rubber bearing stiffness. Combining multiple dynamic and FEM theory, we build propulsion shaft rigid-flexible coupling dynamic model and discuss the influence of stern bearings’ stiffness. Results show that: In a certain scope, water-lubrication stern tube bearing’s stiffness changes in linear rule to the length-diameter ratio, and nonlinear change to radius ratio. Bearings’ stiffness has little influence on reaction force, but has much influence on displacement acceleration.

Abstract: Based on ANSYS software and combined with the theory trends on stern shaft seal performance, the steady-state thermal structure coupling and transient thermal structure coupling analysis of stern shaft mechanical seal had been carried on. It showed that the transient thermal structure coupling analysis was more close to the actual condition of stern shaft seal. The result of transient state analysis indicated the thermal-mechanical effect on seal face during starting, and showed that the contact area was decreased especially the temperture rise rapidly inside of the seal.

Abstract: The friction coefficient changes of water lubricated rubber bearing according to the temperature under different pressures are tested in the tribology test. The vibration data are collected and processed by B&K PULSE Analyzer Platform and the influences of temperature on the friction coefficient and vibration are analyzed. The results show that the influences of temperature on friction coefficient and vibration are immense; the friction coefficient increases along with temperature rising, especially when the bearing is at a low speed. And the vibration of the bearing is more serious.

Abstract: In order to investigate the failure mechanism of water-lubricated rubber bearings based on the method of time domain and frequency range of vibration signals, the characteristic performance is analyzed when there is failure and it is found that the abnormal vibration has relations with the contact pressure and the negative curve of speed-friction coefficient. Furthermore, some failure forms are quoted and applied to analyze the fault diagnosis of the rubber bearings. At a certain speed range and specific pressure, when the contact pressure is larger and the friction coefficient is higher, the vibration will be more obvious. Moreover, there are some preventive measures to avoid or eliminate potential hidden troubles.