Planning of thermal-hydraulic tests of pipeline systems with the methods of active identification★

The lack of reliable information about actual characteristics and parameters is the main deterrent to the effective application of mathematical and computer-modelling methods for solving problems of optimal reconstruction, adjustment, development of operational condition, dispatching control of pipeline systems. The paper presents the original formalization of the problems of testing pipeline systems for hydraulic and thermal losses as problems of active identification, assuming optimal planning and processing of experimental results on the basis of attracting a mathematical model of steady-state thermal-hydraulic state. The proposed technique consists in a stepwise testing strategy that ensures the extraction of maximum information with a minimum risk of excessive testing, is applicable for different types of testing of pipeline systems of arbitrary structure and configuration. Theoretically, and for an illustrative example, the potential efficiency of combining thermal and hydraulic tests of pipeline systems is shown, which is manifested in minimizing the total number of experiments to obtain a given accuracy in determining the actual characteristics of pipeline systems and the predictive properties of the model

Study of the measurements placement problem for planning of the optimal experiment

Both in Russia and abroad, there are works that are devoted to the problem of optimal placement of measuring devices, which are evidenced by the current literature. The proposed methods are not universal, that does not allow them to be directly used for different types of pipeline systems. In addition, the developed algorithms does not guarantee a global solution. In this regard, there is a demand for solving the problem of optimal placement of measuring devices for pipeline systems. At the same time, not only the number and accuracy of measuring devices, but also their composition and placement locations are important. In this paper, a mathematical formulation of the problem of optimal placement of measuring devices is given, methods for its solution are proposed. The numerical example shows the effectiveness of the proposed method of optimal placement of measuring devices, which allows to get a global solution for a previously known finite number of steps

Quantitative assessment of the identifiability of pipeline systems

The article is devoted to the issues of quantitative assessment of the identifiability of the pipeline systems (heat, water, gas supply systems etc.). Identifiability is first considered as a complex property, including such particular properties as observability and parametric identifiability. A brief description of the topic relevance and a review of available development in this sphere allow giving the structuring of identifiability analysis problems. The technique of differentiate quantitative analysis of this property is disclosed. It based on the use of analytical expressions for covariance matrices of parameters. New concepts of experimental matrices, parametric identifiability and observability of pipeline systems are introduced. Analytic expressions for these matrices are given. The substantiation of the integral indicators of the pipeline systems identifiability is presented, including the covariance matrix determinant for the estimated parameters and the relative variance of the prediction for non-measurable state parameters. The analytical interrelation of these indicators is opened. These indicators can be accepted in a role of criteria at decision of synthesis problems for optimal measurements composition

Quantitative assessment of the identifiability of pipeline systems★The research was carried out within the project III.17.4.3 of the Fundamental research program of SB RAS (AAAA-A17-117030310437-4)

The article is devoted to the issues of quantitative assessment of the identifiability of the pipeline systems (heat, water, gas supply systems etc.). Identifiability is first considered as a complex property, including such particular properties as observability and parametric identifiability. A brief description of the topic relevance and a review of available development in this sphere allow giving the structuring of identifiability analysis problems. The technique of differentiate quantitative analysis of this property is disclosed. It based on the use of analytical expressions for covariance matrices of parameters. New concepts of experimental matrices, parametric identifiability and observability of pipeline systems are introduced. Analytic expressions for these matrices are given. The substantiation of the integral indicators of the pipeline systems identifiability is presented, including the covariance matrix determinant for the estimated parameters and the relative variance of the prediction for non-measurable state parameters. The analytical interrelation of these indicators is opened. These indicators can be accepted in a role of criteria at decision of synthesis problems for optimal measurements composition

Modern Experience in Dynamic States Simulation of Pipeline Systems and the Possibility of its Application to Solving Identification Problems

The effectiveness of solving the problems of development, reconstruction and control of pipeline systems is directly related to the level of application of methods for mathematical modeling and computer technology, which cannot be provided in isolation from the problems of reliability of information about their actual characteristics and parameters, as well as the degree of adequacy of used models. These problems constitute the content of identification tasks. The trend of transition to intelligent pipeline systems requires consideration of their control processes in real time, and hence the consideration of identification problems as passive identification problems based on the results of dynamic measurement data. The article provides an analysis of the existing experience in the field of dynamic states modeling of pipeline systems of various types and purposes, as well as mathematical formulations of the identification problem depending on the degree of parametric and state nonstationarity of systems, on the method and rate of data acquisition

Technologies for mathematical and computer modeling to automate the process of operational states development for heat supply systems

This article proposes the new technology for development of operational states for HSS of arbitrary structure and dimension. Technology is based on multilevel modeling and a new method for adjustment calculation of thermal hydraulic states. It is implemented in the information and computer complex «ANGARA-HN». Technology includes checking the permissibility of states, calculating the throttling devices on the network and inputs of consumers’ buildings. It allows calculating large systems with intermediate stages of regulation, developing adjustment measures to improve the quality of heat supply and consumer provision, reducing circulation flow rates and pressure in networks. The development of modeling methods is carried out in the following directions: taking into account the new composition of equipment, including mixing pumping stations; development of nontraditional methods of calculation, such as object-oriented modeling; development of tasks of hierarchical optimization and identification of state parameters, as task of rising for model adequacy; development of task for finding of sectioning variants for multi-circuit heat network with several sources. The application of methodological and software developments makes it possible to obtain both an economic and a social effect by identifying and realizing of the energy saving potential, improving the quality and reliability