Pipe resistance coefficients identification of water networks considering solvable conditions

To make hydraulic models more accurate and realistic, this paper proposes a method to identify pipe resistance coefficients (PRCs) by using the measured heads at partial nodes. A successive linearization method is adopted to solve for the pipe flows, node heads, and PRCs. Based on the matrix analysis theory, the relationships among the number and location of measurement sites, number of hydraulic conditions (HCs), and solvable condition of PRC identification are established. The proposed method can identify all the PRCs when a solvable condition can be satisfied. In addition, the analysis process can be used as a tool to evaluate whether a given arrangement of measurement sites can meet the solvable condition of PRC identification, and to determine the minimum number of HCs. The performed case studies verified the feasibility of the proposed method, and the determined accuracy of PRC identification was noted to satisfy the actual engineering requirements.

A Novel Method for the Dynamic Coefficients Identification of Journal Bearings Using Kalman Filter

The dynamic coefficients identification of journal bearings is essential for instability analysis of rotation machinery. Aiming at the measured displacement of a single location, an improvement method associated with the Kalman filter is proposed to estimate the bearing dynamic coefficients. Firstly, a finite element model of the flexible rotor-bearing system was established and then modified by the modal test. Secondly, the model-based identification procedure was derived, in which the displacements of the shaft at bearings locations were estimated by the Kalman filter algorithm to identify the dynamic coefficients. Finally, considering the effect of the different process noise covariance, the corresponding numerical simulations were carried out to validate the preliminary accuracy. Furthermore, experimental tests were conducted to confirm the practicality, where the real stiffness and damping were comprehensively identified under the different operating conditions. The results show that the proposed method is not only highly accurate, but also stable under different measured locations. Compared with the conventional method, this study presents a more than high practicality approach to identify dynamic coefficients, including under the resonance condition. With high efficiency, it can be extended to predict the dynamic behaviour of rotor-bearing systems.

FUNCTIONAL STRUCTURE OF OPERATING PROCESSES AT MARINE LOADING COMPLEX OF MODERN EXPORT COAL TERMINALS

The article focuses on the problem of identifying the functional structure of the processes occurring on marine cargo handling area with modern export coal terminals using machines of continuous transporting (conveyor mechanization). Methods of data analysis and data mining allow to form a complete picture of the cycle of ship-loading operations and downtime, which are taken into account within the “ignorance” coefficients in the Russian regulatory framework of technological design of seaports. Today, designing high-tech terminals using “ignorance” ratios is found as archaism, because it reduces the calculated results of the throughput capacity of coal export terminals by 50-60%. The main purpose of the terminal functioning is the principle of economic efficiency: it is necessary to understand in detail the technological processes and to perform ship loading operations without exceeding the lay time to avoid additional costs for demurrage. For marine terminals it is important to identify, deeply understand and manage the factors hidden behind these coefficients. Identification of the functional structure of the marine side processes allows to influence on them, more efficiently operate the terminal and reduce the range of uncertainties, increasing the throughput of the marine side using the principles of the technical limit. Considered detailing the processes can be used as a toolkit for creating more accurate methods of calculating the throughput capacity of the maritime side, as well as being an informative description of simulation models. The use of detailed parametric probabilistic design models will allow achieving transparency in the relationships “a design engineer - a client” and generating results in terms of the most probable amounts of throughput and the potential for increasing freight turnover.