Authors: L.R. Xia, Niao Qing Hu, G.J. Qin
Abstract: Turbopump is a high-fault-rate component in Liquid Rocket Engine (LRE). The research on real-time process monitoring technology and system for turbopump is vital to increase the reliability and safety of LRE. In this paper, three real-time process monitoring algorithms for turbopump were studied firstly, on the basis of monitoring parameters selection and multiple domain feature extraction. Then, the real-time monitoring system realized by means of PXI (PCI eXtensions for Instrumentation) controller was introduced. And, aiming at the shortage of the previous system, the real-time process monitoring system based on DSP (Digital Signal Processor) for turbopump was studied to realize higher computing speed, which could conduce to extract multiple domain features and run manifold real-time monitoring algorithms. The new system could also satisfy the small-sized requirement in engine flying state.
463
Authors: Wen Hui Tan, Lei Zhang, Dan Qing Gao, Ya Liang Li
Abstract: How the mechanical parameters of rock change with the development of joints and fractures is still a puzzle. It is hard to measure rock joints accurately at present. Resistivity is an important parameter of rock and its value can reflect the degree of fragmentation of rock. A new method combining measurement method of Young’s modulus with resistivity survey method is proposed in this paper. To determine the variation of mechanical parameters in the process of rock damage, the uniaxial, tri-axial compression tests and resistivity survey on rock specimens are done. The results showed that the values of resistivity were continuously increasing, but Young’s modulus and mechanical parameters were decreasing in the process of rock damage. The relationships between resistivity and mechanical parameters are established based on the experiments in the process of rock damage. Therefore, the damage state of rock and the change of mechanical parameters of rock can be determined according to the variance of resistivity. The study is helpful for design and real- time stability evaluation on rock engineering.
1849
Abstract: According to the requirements of states monitoring and detection to shearer, it is an urgent need to develop a new states signal collection method, which can solve the current problem in signal collection. In this paper we collect shearer’s states signal by using self-developed portable intrinsically safe mining vibration recorder, which has solved the data acquisition problem of vibration-based shearer fault diagnosis research. This has laid the foundation for states monitoring and detection to shearer, and also for remote monitoring and fault diagnosis to shearer. At the same time, this will provide theoretic reference and basis for design improvement and performance improvement of shearer in future through analyzing the data.
963
Authors: Wen Xia Zhang, Hua Guo, Yuan Wang, Yu Liu
Abstract: For the purpose of fast fault diagnosis and fault time point location, wavelet transform was used in the fault diagnosis in this paper, due to its singularity of the wavelet transform and multi-resolution properties, and it is verified the simulation examples, which illustrates different wavelet coefficients have different effect on the detection of mutation signal. Finally we obtained a general method of wavelet type selection.
468
Authors: Shou Xu Song, De Qiao Yu, Hui Cha
Abstract: A new method to recycle radial tyre is studied, using Ultra-High Pressure Water jet to cut the tread rubber. The dynamic constitutive model of radial tyre material is builded, fitting model parameters with least square method. And the stress distribution law and dissociation characteristics of rubber block under impact are studied by finite element analysis.Through the SEM observation of cross section, the relationship is preliminarily discussed between stress distribution and micro-morphology of fracture interface and dissociation pathways. The split Hopkinson pressure bar apparatus is used to obtain the dynamic response law of material in a wide range of Strain Rate. The experimental results show that viscoelasticity of the rubber material is not fully reflected from the perspective of the stress wave propagation. The rubber material has a brittle transition and eventually forming fine powder. And the experimentally measured material crushing threshold is found agreed well with the numerical simulation results. It provides important mechanical foundation for further research on the mechanical force desulfurization of material.
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