Operating conditions of container cars in railway trains of special formation

The article considers main technical characteristics, indicators of dynamic qualities and parameters of braking effciency of special railway rolling stock of container cars (container transporters) intended for the transportation of radioactive materials — spent nuclear fuel. In accordance with the current regulatory documents of JSC Russian Railways, it is currently allowed forming special trains exclusively from container transporters of any one type, which is associated with the peculiarities of the technology for handling and transporting spent nuclear fuel, which is within the competence of the state corporation Rosatom. However, this signifcantly increases the timing of the delivery of special trains due to the need to wait for the readiness of transporters, due to the non-simultaneous delivery of any one type of assembly kits with spent nuclear fuel. The practice of handling has shown that the transportation of some types of spent nuclear fuel can be carried out with a combination of the transport operation, which implies the combination of various types of container transporters in one echelon, but at the same time it is necessary to correct certain regulatory documents of Russian Railways. For this purpose, at the request of the Rosatom corporation, a necessary set of experimental works was carried out. Authors presented results of control running dynamic, stationary and running braking tests of container transporters of various types, following as part of the same echelon, on the infrastructure of the Test Loop of JSC “VNIIZHT”, including when running along the frst ring track and along various combinations of turnouts along a tangent line (main) and lateral directions. It has been experimentally proved that it is possible to operate container transporters of various types as part of the same echelon in compliance with the conditions for ensuring traffc safety in accordance with the standards of dynamic qualities and braking effciency. Based on the test results, a regulatory document of JSC Russian Railways was developed — the Regulation on the conditions for joint operation of special freight cars (transporters) as part of one echelon, approved by the order of JSC Russian Railways dated July 22, 2021 No. 1591/r. components. Interstate standard, put into effect as nat. standard of the Russian Federation by order of the Federal Agency for Technical Regulation and Metrology dated March 17, 2016 No. 162-st. Moscow, Standartinform Publ., 2016, 54 p. (in Russ.).

ANSYS-CFX simulation of the SRBTL test loop core with nanofluid coolant

In the present study, CFD calculations are presented for the three types of water-based nanofluids Al2O3/water, CuO/water and TiO2/water with 0.1% volume fraction. These calculations are done with ANSYS-CFX and as geometry the SRBTL test loop as scaled down test loop for a VVER-1000 reactor core design is used. The goal of this study is to evaluate the CFD program against the SRBTL test loop core as a scaled core for applying water-based nanofluids as coolant. ANSYS-CFX simulation data are validated against the RELAP5/MOD3.2 simulation data for pure water. This comparison shows a good agreement. The simulation results for the nanofluids and water including Re number, temperature, viscosity, pressure drop and heat transfer coefficient through the SRBTL test loop core are compared. The results of the comparisons show that the SRBTL test loop core is suitable to extract experimental data of water-based nanofluids for using them as coolant in the VVER-1000 reactor.

Railway Science: Results of the I International Scientific and Practical Conference “Research 1520 VNIIZHT: Look Beyond the Horizons”

In a constantly changing world, any production activity, including transport, requires scientific support, which, in turn, involves the active participation of scientists, as well as the possibility of exchanging views between theorists and practitioners. One of the most effective formats for this is a scientific conference, which allows discussing long-term trends in the development of the industry and ways of early adaptation to them. In the railway sector, scientific conferences have become a regular and effective tool for discussing promising trends in the industry.President of the Russian Federation Vladimir Putin declared 2021 the Year of Science and Technology. In this regard, it is symbolic that on August 26–27, 2021, the 1st International Scientific and Practical Conference “Science 1520 VNIIZHT: Look Beyond the Horizons” was held on the territory of Test Loop of the JSC “VNIIZHT”. The JSC Railway Research Institute, a leader in the development, creation, testing and implementation of railway equipment and technologies in the 1520 mm track space organized the conference. At the conference, reports were presented both by practitioners and acting managers, and by theoretical scientists. The conference was organized in the form of parallel working sections, the main results of which were discussed at a panel discussion. According to the presentation of the heads of the thematic sections, the best speakers were awarded with diplomas, including many young scientists. According to the assessments of managers and employees of railway enterprises and suppliers, the conference was a useful and longawaited international event in railway science and practice.

Experimental and Numerical analysis of Flow characteristics of sand water slurry in a horizontal pipe

The transportation of the solid material using hydraulic transportation method is economically the best method. The head loss occurs during transportation of slurry through horizontal pipelines usually depends on the rheological behavior of slurry, slurry concentration, particle size, and influx velocity. An experimental investigation has been performed using sand-water slurry flowing through the horizontal pipe section of a pilot plant test loop. The head loss obtained from the experimental results was validated through CFD simulation using FLUENT. The solid concentration of sand-water slurry and influx velocity used during both experiments and numerical simulation were in the range of 10-40% (by weight) and 1 to 4 m/s respectively. The numerical simulations were performed using five different turbulence models and the results obtained using SST k-omega model was in close agreement with experimental results. It is observed from both the experiment and numerical analysis that the pressure loss, granular pressure, volume fraction and skin fraction coefficient during transportation of slurry through a horizontal pipe is a function of solid concentration and influx velocity. The present study observed that as the flow velocity increases four times, the pressure loss is increasing more than 10 times. Uniform volume fraction at middle zone of outlet of the pipe is observed as both the slurry concentration and velocity of flow increases.

A pre-test analysis of ATLAS SBO with RCP seal leakage using MARS code

The accident in Fukushima Daiichi nuclear power plants shows the important of developing coping strategies for extended station blackout (SBO) scenarios of the nuclear power plants (NPPs). Many NPPs in United State of America are applying FLEX approach as main coping strategies for extended station blackout (SBO) scenarios. In FLEX strategies, outside water injection to reactor cooling system (RCS) and steam generators (SGs) is considered as an effective method to remove residual heat and maintain the inventory of the systems during the accident. This study presents a pretest calculation using MARS code for the Advanced Thermal-hydraulic Test Loop for Accident Simulation (ATLAS) SBO experiment with RCP seal leakage scenario. In the calculation, the turbinedriven auxiliary feed water pumps (TDAFPs) are firstly used after SBO initiation. Then, the outside cooling water injection method is used for long term cooling. In order to minimize operator actions and satisfy requirements of APR1400 emergency operation procedure (EOP), the SGs Atmospheric Dump Valve (ADV) opening ratio, auxiliary feed water (AFW) and outside cooling water injection flow rates were investigated to have suitable values. The analysis results would be useful for performing the experiment to verify the APR 1400 extended SBO optimum mitigation strategy using outside cooling water injection.

Validation of a Miniaturized Test Loop for the Assessment of Human Blood Damage by Continuous-Flow Left-Ventricular Assist Devices

Despite improved hemocompatibility of left-ventricular assist devices (LVADs), assessment of blood damage remains mandatory in preclinical testing as standardized by ASTM-F1841. The most relevant test fluid is fresh, non-pooled human blood, but the limited volume of a standard donation requires significantly smaller loops than those commonly used with animal blood. In a recent study with porcine blood, we verified a miniaturized test loop with only 160 mL for the ASTM-conform paired testing of at least two LVADs and a static reference. Here, we validated this mini test loop for standardized assessment of blood damage with one 450-mL single donation of fresh human blood. Blood damage was assessed for HeartMate 3 and BPX-80 in 9 experiments with heparinized human blood for 6 hours. We analyzed plasma free hemoglobin, von Willebrand factor (vWF) concentration and collagen-binding functionality and calculated indices of hemolysis and vWF-ratios. Overall, we observed less blood damage compared to our previous study; however, the differences in mean indices of hemolysis and in mean normalized vWF-ratio between BPX-80 and HeartMate 3 were consistent for human blood. Thus, our mini test loop proved to be valid for preclinical standardized assessment of blood damage with only 450 mL of fresh human blood.