Fluid mechanics tests of separator-reheater turbines

The main aim of the current work is to increase operation efficiency and reliability of moisture separator-reheaters and turbines of NPPs. As the experience from MSR-500-1 operation showed the presence of large disperse moisture leads stops of the turbine. The high wetness level of steam downstream of separating devices observed since the first years of operation. Results from tests of the modernized separator-reheaters of the first unit at the Smolensk NPP with «Powervane» louvers developed by Balcke-Durr company are presented. Results from studies on the determination of wetness of the steam at the outlet from the separating part of the MSR-14, MSR-24, which demonstrate advantages of modernized construction are discussed. Modernization of separator-reheaters of the turbines TG-1, TG-2 resulted in eliminating non-uniformity of wetness over the perimeter and height of the steam space downstream the separation units. Success in modernization was caused by arranging separate outlets for moisture depositing at the walls, bottom of the inlet chamber. According to the results of the carried out studies an average value of the wetness at the outlet of the separation units was 0.6% which is close to the design value 0.5%

High-temperature service life tests of full-size thermosyphons

During past two decades, at temperature 240-265°C, resource tests were carried out on 19 thermosyphons of full-scale sizes: 45х4 mm in diameter, 4.92 m in length. The thermosyphons were prepared with varying preliminary surface treatment methods, composition of the aqueous solution to be poured into the thermosyphons, location of titanium chips in the perforated capsules under the lid of the thermosyphons. With a period of 1 to 3 years, thermosyphons were removed from testing system for 30 hours to control the vacuum by thermal method that does not require depressurization. At the last control experiment, four thermosyphons are depressurized for the following purposes: to check the condition of their internal surface in different zones along the length; for the chemical analysis of the aqueous solution poured from them; to determine the structure and characteristics of the mechanical properties of the thermosyphon metal. The main aim of the tests is to justify maintaining the structure and mechanical properties of the metal for a long time, keeping a vacuum of 90-95% inside the thermosyphon, ensuring high heat transfer characteristics of the boiling operating mode of thermosyphons

Numerical investigation of a moisture wave-type vane separator

This study aims to determine the appropriate method for modeling separation processes in wave-type moisture vane separators and to analyze possible design improvements of the typical wave-type vane separator using numerical simulation methods. It discusses conditions of the secondary droplets generation phenomena. The applicability of the particle transport method for modeling the working process in wave-type vane separators is confirmed. The study explores the water droplets distribution pattern in the dispersed two-phase flow of a separator. A numerical study of the workflow in the typical steam-water separator with wave-type vanes was carried out. A dispersed two-phase flow in a separator is modelled as two separate flows. Dry saturated steam is considered as a continuous medium using the Euler method; the liquid phase is represented as a stream of water droplets described by the Lagrange method. Authors propose an option of modernization of the separator design applying three drainage channels on the path of small droplets

Cooling of a battery pack of a car, working on renewable energy

The aim of the work is to choose a method of a solar car battery cooling. The student engineering team of Peter the Great Petersburg Polytechnic University designs the car. The analysis of the electrical circuit of the battery is carried out, the heat release is estimated due to three factors. According to the conditions of reliable operation of the battery, it is necessary to maintain its temperature range below 45°C, which requires cooling. The paper analyzes the possibilities of liquid, air-cooling, compares the free and forced methods of convective heat transfer. For the normal operating mode of the electric vehicle, environmental temperature at the level up to 38°C, a criterion thermal engineering calculation of the forced air-cooling of the corridor assembly of 405 battery cells providing the required heat dissipation is performed. It is shown that relatively high values of the heat transfer coefficient are provided under turbulent flow conditions characterized by Reynolds criteria above 103. On the basis of an analysis of the steady-state stationary heat-removal regime, it was concluded that an air flow provides a temperature gradient, sufficient for cooling the lithium-ion battery of a Solar Car «Polytech Solar»

Cooling of a battery pack of a car, working on renewable energy

The aim of the work is to choose a method of a solar car battery cooling. The student engineering team of Peter the Great Petersburg Polytechnic University designs the car. The analysis of the electrical circuit of the battery is carried out, the heat release is estimated due to three factors. According to the conditions of reliable operation of the battery, it is necessary to maintain its temperature range below 45°C, which requires cooling. The paper analyzes the possibilities of liquid, air-cooling, compares the free and forced methods of convective heat transfer. For the normal operating mode of the electric vehicle, environmental temperature at the level up to 38°C, a criterion thermal engineering calculation of the forced air-cooling of the corridor assembly of 405 battery cells providing the required heat dissipation is performed. It is shown that relatively high values of the heat transfer coefficient are provided under turbulent flow conditions characterized by Reynolds criteria above 103. On the basis of an analysis of the steady-state stationary heat-removal regime, it was concluded that an air flow provides a temperature gradient, sufficient for cooling the lithium-ion battery of a Solar Car «Polytech Solar»

Increasing the efficiency of nuclear power plant equipment at the design stage

It is possible to increase the efficiency of the nuclear power plants equipment in various ways. In particular, one of the most relevant is the active use of computer modeling at different stages of work. The effectiveness the software package used directly affects the quality of the installation equipment. Depending on the stage at which the software package is used, it has various priority properties for the most effective application

Comparative efficiency of applying heat pumps within the system of disposal of the condensation heat of heat machines for heating ice arenas

The analysis of the application of two energy-efficient technologies for air heating of ice arenas is considered, such as the use of heat pumps and a system for partial utilization of heat of condensation of heat engines. The actual energy costs during the operation of two systems are studied, such as the consumption of heat and electricity from heat and power supply organizations, as well as the costs of modernization. The weaknesses and positive aspects of the studied systems for air heating of ice arenas are revealed. Comparison of the calculated data obtained as a result of calculations with the actual data obtained in the research institution in which the study is carried out. An example of actual effective modernization of existing engineering systems is shown, as a result of which the energy efficiency of existing systems is increased. Additionally, we have performed the calculation of reducing thermal pollution with introduction of the investigated systems

The new ways to increase the efficiency of thermal hydraulic processes in systems of separation and reheating of NPP wet steam turbines

Systems of moisture separators - reheaters (SMSR) were created simultaneously with the powerful turbines development of nuclear power plants operating on a wet steam from the early 60s of the 20th century. This lengthy experience made the opportunity to identify the moisture separators - reheaters (MSRs) drawbacks, to determine the objectives for their design and computation improvement in order to increase thermodynamic efficiency, MSR devices and MSR systems reliability in general. Based on maintenance experience and results of our and other researchers’ model and field studies this article discusses potential ways of further development and improvement, taking into consideration both SMSR components (separation and reheating) under conditions of their flow in one apparatus

Steam reheater with helical tube bundle for wet steam turbine

Since steam heat exchangers, used at steam cycle of Russian nuclear power stations, were designed while the knowledge about the separation and the heat exchange processes was limited, deviations between its empirical and theoretical characteristics occur. This limitation also determined application of heating pipes with simple straight shape rather than curved. This study explores a steam heat exchanger with helical heating pipes. It was shown that the model may work stably within the range of parameters, simulating work conditions of the moisture separator and steam reheater at Leningrad nuclear power plant. The experiment included processing of pure water steam as well as mixture of steam and nitrogen. It was obtained a relationship between empirical the heat transfer coefficient and the steam mass flow rate. It was noted that presence of incondensable gas does not affect significantly the heat transfer from the coils, processing high pressure steam

Russian and foreign steam generators for NPP power units with wet steam turbines

The main aim of the current study is to analyze advantages and shortcomings of horizontal and vertical types of steam generator design. Design solutions and experience of operation of steam generators of horizontal type accepted in Russia and of vertical type applied by Westinghouse, Combustion Engineering, Siemens, Mitsubishi, Doosan were analyzed within the framework of the present study. It was established that steam generator equipment of horizontal type is characterized by disadvantages of design, technological and operational nature. Thus, horizontal steam generators with dimensions permissible for railroad transportation and, for VVER-1200 with reactor vessel diameter equal to 5 m, by water transport as well, have exhausted the possibilities for further significant increase of the per unit electric power. The demonstrated advantages of vertical-type steam generators are as follows: 1) absence of stagnant zones within the second cooling circuit; 2) uniformity of heat absorption efficiency of the heating surface that ensures improved conditions for moisture separation; 3) increased temperature drop with parameters of generated steam elevated by 0.3 – 0.4 MPa. Conclusion was made on the advisability of introduction of steam generators with vertical-type layout in the Russian nuclear power generation