Mathematical modeling of technological objects and systems through the eyes and hands of a student

Traditionally, Rosatom pays special attention to training and supporting the comprehensive development of young talents, including in engineering and mathematics. In previous articles, we described in detail how to model in REPEAT, an in-house development of the JET Engineering and Technical Center. But we not only model on REPEAT ourselves, but also teach it to the guys from their student days. Educational centers based on REPEAT – Simulation Schools – opened in the country’s leading universities become a powerful center of digital competencies for students, and also ensure their familiarity with domestic simulator technology, founded by the JET Research Center more than 30 years ago and still used today. Read more about our Modeling School project below.

Looking ahead, I will say that today we are opening a series of articles devoted to work in the field of mathematical modeling from our students – students of Modeling Schools. Observing the progress of novice IT engineers in mastering the art of mathematical modeling on REPEAT, we decided that a scientific school in the field of development of digital twins and other digital areas was emerging before our eyes – and it was based on domestic software. Together we are discovering new possibilities of the REPEAT software, and we look forward to new achievements and discoveries to be made together with the students and teachers of our common project School of Modeling.

Let’s start publishing reasons for pride with cases developed by the team of the Kuban State Technological University – these are talented students of the Department of Thermal Power Engineering and Heat Engineering and their equally talented teachers. Together they are forging their own path in the field of digital twin research and development, and REPEAT is actively helping them along the way.

Link to telegram channel REPEAT: https://t.me/repeatlab

Project School of Modeling JSC ITC “JET”

The project was initiated in 2022 and is aimed at reducing the adaptation time for young specialists in the production environment of companies by acquiring practical skills while still studying at universities, as well as forming a permanent personnel reserve for the needs of the industry in the field of mathematical modeling.

By opening competency centers in the best technical universities of the country, JET continues to provide comprehensive support for the effective organization of the educational process – provides the university with software products for educational activities, conducts internships for teaching staff, transfers educational materials, provides advice and support to both teaching staff and students .

Students, mastering modern technologies on the unique REPEAT modeling platform, have the opportunity to gain skills in working on a Russian digital product in terms of mathematical modeling and programming.

The work of the Modeling School is closely related to interaction with existing or potential customers. Students get the chance to take part in solving business problems of commercial companies already from their student days, which gives them an undeniable advantage in employment and distinguishes them in the IT market. Such experience allows us to form a strong driver for the digital transformation of key sectors of the economy in the future.

Based on the results of the training, all graduates of the School of Modeling are awarded certificates of completion of the course, and students who presented high-level projects are recommended for priority employment in JSC ITC JET and other organizations of the State Corporation Rosatom.

During their studies at the School, students will master modeling skills and other competencies, including:

– development of models of objects and technological systems;

– creation of digital twins;

– conducting virtual tests of the designed equipment.

As a result of the training, students can gain skills in operating nuclear power plants, knowledge in the field of design and engineering, and broad digital competencies in general.

The network of JET engineering and mathematics schools is actively expanding. In 2022, two Modeling Schools were opened: at the Kazan State Energy University (KSEU) and Tomsk Polytechnic University (TPU). A total of 25 senior students were selected for the School. During two academic semesters, students studied 4 academic hours weekly. At the end of the academic year, a final summary of knowledge was carried out, demonstrating the level of preparedness of students in terms of mastering JET software products. Based on the results of intermediate and final assessments, 5 School students have already been hired at JET: four TPU students have been employed in the regional office of JET in Tomsk, one KGEU student has been relocated and employed in the head office in Moscow. Further development of graduates of the School of Simulation takes place on real company projects, under the sensitive mentoring of experienced engineers.

In the fall of 2023, four more Modeling Schools were opened on the basis of technical universities: NRU MPEI (Moscow), DGTU (Rostov-on-Don), KubSTU (Krasnodar), URFU (Ekaterinburg).

So, we present to you a work on the development of digital twins in heat supply – where they play a special role. In the era of digitalization, engineers and developers face complex challenges. Digital twins in systems management open up new possibilities for engineering. Students of the Department of Electrical Engineering of Kuban State Technical University, within the framework of the “School of Modeling”, under the leadership of Dmitry Batko, successfully developed a model of a central heating point, demonstrating an approach to numerical methods. Taking into account the multifactorial nature and complexity of interactions within the system, the use of a mathematical modeling tool makes it possible to establish more effective control and management of the heat supply of an object, and reduce the risk of emergency situations.

PART 1: DIGITAL TWIN OF THE HEATING SYSTEM

Batko D.N. Senior Lecturer, Department of TET, Kuban State Technical University, Arushanyan R.R. senior lecturer of the Department of TET KubSTU, Denevich A.A. 4th year student of Kuban State Technical University, Rozina D.E. 4th year student of KubSTU

Kuban State Technological University, Krasnodar

This paper presents the results of a mathematical model of a central heating point (CHS) using the System of Automatic Design of Physical Engineering Calculations (SAPHIR) developed by JSC ETC JET. Verification of calculated and experimental data showed good convergence of the main parameters. The obtained data were compared for ten operating modes. Analysis of the calculation results showed sufficient accuracy of the model (the error does not exceed 1%).

Key words: central heating point, mathematical model, efficiency of the heat supply system.

The main task of heat supply is a high-quality and energy-efficient supply of thermal energy to consumers. For efficient heat supply, it is necessary to provide each consumer with the necessary amount of thermal energy with minimal losses and costs. Today, thermal energy consumption differs significantly from calculated values. Non-standard supply of thermal energy with centralized heat supply is due to problems with the operation and condition of heating networks in Russia.

Mathematical modeling in heat supply allows us to develop and optimize the required operating modes and operation of equipment, allowing us to solve the assigned problems.

This paper presents the results of the development and verification of a mathematical model of a central heating point using the System for Automatic Design of Physical Engineering Calculations (SAPHIR) developed by JSC ITC JET.

The object of modeling was a central heating station that provides a heating system for two groups of consumers. The central heating station is connected to the heating networks of Krasnodarteploset JSC. The principal design diagram is shown in Figure 1.

1 – plate heat exchanger of consumer No. 1; 2 – consumer plate heat exchanger No. 2; 3 – consumer control valve No. 1; 4 – consumer control valve No. 2; 5- circulation pumps of consumer No. 1; 6 – consumer circulation pumps No. 2; 7 – charging pumps of consumer No. 1; 8 – group of expansion membrane tanks with a total volume of 2.4 m3 of consumer No. 2; 9 – group of expansion membrane tanks with a total volume of 2.4 m3 of consumer No. 1.

The heating system is connected according to a scheme with independent connection to the heating network. Consumer No. 1 is connected through a plate heat exchanger type NN – 41 from Ridan LLC with a heating area of ​​44.55 m2. Consumer No. 2 – through a plate heat exchanger type NN – 41 with a heating area of ​​38.35 m2. The design coolant flow rate of consumer No. 1 G1=62.5 m3/h is provided by circulation pumps IL80/150-7.5/2 from WILO with frequency regulation. Coolant consumption of consumer No. 2 G2=53.6 m3/h. provide circulation pumps IL80/140-7.5/2.

The coolant temperature in the heating system is regulated for each consumer by a two-way control valve VFS2 Du50 (KVS=40) with an AMV35 electric drive from Danfoss. The calculated parameters of the heating system coolant change according to the 95/700C schedule depending on the outside air temperature.

When developing a mathematical model, a diagram of a heating point was drawn up with the parameters of the elements specified in accordance with the data of the manufacturer and design documentation.

The geometric parameters for the pipelines were determined (the inlet and outlet diameters did not change). Pump modeling was carried out according to the flow-pressure characteristic.

The control valves were adjusted according to the manufacturer’s specifications for the appropriate throughput. The heat exchanger was modeled with two elements. Each element is part of an independent heating and heated coolant circuit. The thermohydraulic mode of heat exchangers was checked in the calibration program of the manufacturer of heat exchangers, Ridan LLC.

Verification of the mathematical model of the central heating station was carried out in 10 operating modes. According to the temperature schedule, the temperature of the coolant in the supply pipeline of the heating network was set, the temperature of the coolant in the return pipeline from consumers, the flow rate in the heating and heated circuits was maintained in accordance with the design documentation. The temperature of the coolant in the supply pipeline to the consumer and the temperature of the coolant in the return pipeline were recorded. The measurement results were compared with the temperature chart data approved by Krasnodarteploset JSC, design documentation and verification calculations of heat exchangers (according to the program of Ridan LLC).

The results of comparison of calculated and design data are given in Table 1. Analysis of the data obtained shows that the mathematical model of the central heating point is adequate. With the chosen degree of complexity of the model, fairly good agreements of the main parameters were obtained. The maximum discrepancy between the calculation results and design parameters is 0.66%.

Conclusions:

The mathematical model of the central heating center, developed in the SAPPHIRE program provided by JSC ITC JET, showed high calculation accuracy (relative error does not exceed 1%).

At the next stage, using a mathematical model of the central heating point, studies will be carried out on the operating modes of the existing heating point in order to determine the impact of changes in the parameters of the heating network (temperature, pressure) on the efficiency of heat supply to consumers.

Bibliography:

Sokolov E.Ya. District heating and heating networks: Textbook for universities. – 7th ed., stereot. – M.: MPEI, 2001. – 472 p.

Shkarovsky, A.L. Heat supply: textbook / A.L. Shkarovsky. – 2nd ed., erased. – St. Petersburg: Lan, 2020. – 392 p. – ISBN 978-5-8114-5222-4.

So, the importance of mathematical modeling of technological systems and objects in modern conditions of digitalization can hardly be overestimated. The results of the work of the KubSTU Modeling School and the mathematical model they implemented for the 1D central heating point will undoubtedly become the starting point for future research and development in this important area.

We thank all participants in this project for their work and diligence. Your reasoning, calculations and research not only deserve high recognition, but also contributed to progress, expanding the horizons of our knowledge. We look forward to the continuation of this fascinating scientific saga!

Inspired by this example, we aim to develop and improve the REPEAT software so that more young scientists can use it and make their own discoveries. There is a lot of interesting things ahead! Join us on this exciting journey through the world of mathematical modeling and discover new horizons of knowledge.