scholarly journals Methodological foundations for the system analysis principles application for modeling the phenomena of heat transfer in the technological cleaning process of tanks for oil products

2021 ◽  
Vol 1083 (1) ◽  
pp. 012046
Author(s):  
S V Fedosov ◽  
A G Azovtsev ◽  
S A Syrbu
Keyword(s):  
Heat Transfer ◽  
System Analysis ◽  
Oil Products ◽  
Cleaning Process

A New Model Towards Thermal Mixing and Stratification in Passive Containment

2013 ◽  
Author(s):  
He Zhang ◽  
Fenglei Niu ◽  
Yu Yu ◽  
Peipei Chen
Keyword(s):  
Heat Transfer ◽  
System Analysis ◽  
Cooling System ◽  
Transfer Problem ◽  
Ambient Fluid ◽  
Simulation Code ◽  
Thermal Mixing ◽  
Lumped Parameter ◽  
Passive Safety System ◽  
Transfer Problems

Thermal mixing and stratification often appears in passive containment cooling system (PCCS), which is an important part of passive safety system. So, it is important to accurately predict the temperature and density distributions both for design optimization and accident analysis. However, current major reactor system analysis codes only provide lumped parameter models which can only get very approximate results. The traditional 2-D or 3-D CFD methods require very long simulation time, and it’s not easy to get result. This paper adopts a new simulation code, which can be used to calculate heat transfer problems in large enclosures. The new code simulates the ambient fluid and jets with different models. For the ambient fluid, it uses a one-dimensional model, which is based on the thermal stratification and derived from three conservation equations. While for different jets, the new code contains several jet models to fully simulate the different break types in containment. Now, the new code can only simulate rectangular enclosures, not the cylinder enclosure. So it is meaningful for us to modify the code to simulate the actual containment, then it can be applied to solve the heat transfer problem in PCCS accurately.

scholarly journals Theoretical Bases of Electrochemical Cleaning of Oil-contaminated Soil

2020 ◽  
Author(s):  
Meshalkin Valeriy Pavlovich ◽  
Shulaev Nikolay Sergeevich ◽  
Pryanichnikova Valeria Valeryevna ◽  
Bykovsky Nikolay Alekseevich ◽  
Kadyrov Ramil Rimovich
Keyword(s):  
Contaminated Soils ◽  
Electrochemical Process ◽  
Oil Products ◽  
Energy Costs ◽  
Cleaning Process ◽  
Reservoir Water ◽  
Optimal Amount ◽  
Effective Removal ◽  
Small Voltage ◽  
Electrochemical Cleaning

This study developstheoretical bases for the electrochemical process of cleaning soils from oil, oil products and highly mineralized reservoir water. The article experimentally and theoretically reveals patterns of reducing the content of polluting oil products in soils of various types during the small voltage passing. The optimal amount of electricity for the effective removal of various types of pollution was required. For the implementation of a electrochemical soil cleaning process a scheme of an original installation with placement of electrodes in the soil was studied. It reduces the resistance between the electrodes. The technical and economical calculations to determine energy costs of the electrochemical installation for cleaning oil-contaminated soils included: the number of electrodes; the voltage depending on the properties of the soil; the area; the depth of contamination of the soil to be treated;azndthe parameters of the electrodes. This allowed us to determine and develop the required degree of cleaning. Keywords: electrochemical process, charge, soil, oil products, voltage, cleaning

Validation Experiment for the Cooling Capability of Passive Auxiliary Feedwater System (PAFS) With PASCAL Facility

2012 ◽  
Author(s):  
Byoung-Uhn Bae ◽  
Seok Kim ◽  
Yu-Sun Park ◽  
Bok-Deuk Kim ◽  
Kyoung-Ho Kang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
System Analysis ◽  
Thermal Power ◽  
Heat Removal ◽  
Steady State Condition ◽  
Single Tube ◽  
Decay Heat ◽  
Validation Experiment

The Passive Auxiliary Feedwater System (PAFS) is one of the advanced safety features adopted in the APR+ (Advanced Power Reactor Plus) which is intended to completely replace the conventional active auxiliary feedwater system. It removes the decay heat by cooling down the secondary system of the SG using condensation heat exchanger installed in the Passive Condensation Cooling Tank (PCCT). With an aim of validating the cooling and operational performance of the PAFS, PASCAL (PAFS Condensing Heat Removal Assessment Loop), was constructed to experimentally investigate the condensation heat transfer and natural convection phenomena in the PAFS. It simulates a single tube of the passive condensation heat exchangers, a steam-supply line, a return-water line, and a PCCT with a reduced area, which is equivalent to 1/240 of the prototype according to a volumetric scaling methodology with a full height. The objective of the experiment is to investigate the cooling performance and natural circulation characteristics of the PAFS by simulating a steady state condition of the thermal power. From the experiment, two-phase flow phenomena in the horizontal heat exchanger and PCCT were investigated and the cooling capability of the condensation heat exchanger was validated. Test results showed that the design of the condensation heat exchanger in PAFS could satisfy the requirement for heat removal rate of 540 kW per a single tube and the prevention of water hammer phenomenon inside the tube. It also proved that the operation of PAFS played an important role in cooling down the decay heat by natural convection without any active system. The present experimental results will contribute to improve the model of the condensation and boiling heat transfer, and also to provide the benchmark data for validating the calculation performance of a thermal hydraulic system analysis code with respect to the PAFS.

On the Benefits of Separating the Heat Transfer Section and Analyzing Elementary Thermodynamic Cycles in Energy Systems Analysis

2008 ◽  
Author(s):  
Matteo Morandin ◽  
Andrea Toffolo ◽  
Andrea Lazzaretto
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
System Analysis ◽  
Internal Heat ◽  
Energy Systems ◽  
Energy System ◽  
Heat Sinks ◽  
Additional Contribution ◽  
Thermodynamic Cycles ◽  
System Configurations

The search for increasing performance and efficiency in energy system analysis leads to complex and highly integrated systems configurations. In a wide variety of energy systems the high integration among components derives from the need of correctly exploiting all the internal heat sources by a proper matching with the internal heat sinks. To address this problem in a general way, in previous works it was suggested to extract from the system flowsheet a “basic configuration” including the components different from the heat exchangers (named “basic” components) and a set of hot and cold thermal flows (without considering the heat exchangers that realize the heat transfer among them). It was also shown how the comprehension of the processes occurring within the system can be strongly facilitated by analyzing separately the elementary thermodynamic cycles involved in the system processes. In this paper, a further step is done by considering the overall efficiency as a baseline efficiency, obtained from the contributions of the separate elementary cycles, with the additional contribution given by the thermal coupling (i.e. the internal heat transfer) among the cycles themselves. The advantages of this analysis are shown using the evolution of the STIG cycle towards more complex system configurations as an example of application.

scholarly journals Oil and oil products market in Ukraine

Ekonomika APK ◽  
2020 ◽  
Vol 312 (10) ◽  
pp. 29-37
Author(s):  
Oleksandr Zakharchuk ◽  
Oksana Vyshnevetska
Keyword(s):  
System Analysis ◽  
Visual Display ◽  
Petroleum Products ◽  
Oil Products ◽  
Refining Industry ◽  
Oil Refining ◽  
Practical Significance ◽  
Research Results ◽  
Destabilizing Factors ◽  
Oil And Oil Products

The purpose of the article is to study the market of oil and oil products in Ukraine, its role in the functioning of agriculture and identify ways to improve. Research methods. Methods used: system analysis and generalization (to study and generalize the energy dependence of Ukraine); statistical (to display the situation on the oil and oil products market in quantitative terms through a system of absolute and relative indicators); analysis of the series of dynamics, structural shifts (to analyze and identify trends in the indicators of the oil and oil products market); comparison (comparison of economic indicators); graphic (visual display of research results in the form of graphs). Research results. The essence and features of the Ukrainian market are revealed, a statistical analysis of trends in the development of the oil and oil products market is carried out, factors influencing the trend of the domestic market are identified and the mechanism of their interaction is clarified. The assessment of the current level of oil independence of Ukraine is carried out. Scientific novelty. The necessity of state support in terms of restoring the competitiveness of the domestic oil refining industry, diversifying the supply of petroleum products to the Ukrainian market and maintaining the share of domestically produced petroleum products at the level of 50% of the consumption volume, as well as reducing the share of other suppliers (importers) to 30% in the total balance has been substantiated. Practical significance. The analysis made it possible to identify destabilizing factors in the oil and oil products market, determine the need for systemic changes in the market functioning model and create conditions for increasing the competitiveness of domestic oil products in the Ukrainian market, create conditions for promoting and stimulating the development of the oil refining industry to weaken the reliability of imports of oil products. Tabl.: 2. Figs.: 1. Refs.: 18.

Natural Convection From a Porous Cavity With Sublayers of Nonuniform Thickness: A Lumped System Analysis

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
R. L. Marvel ◽  
F. C. Lai
Keyword(s):  
Heat Transfer ◽  
System Analysis ◽  
Numerical Study ◽  
Temperature Fields ◽  
Porous Cavity ◽  
Nonuniform Thickness ◽  
Sublayer Thickness ◽  
Vertical Walls ◽  
Quick Estimate ◽  
Rayleigh Numbers

A numerical study has been performed to further investigate the flow and temperature fields in layered porous cavity. The geometry considered is a two-dimensional square cavity comprising of three or four vertical sublayers with nonuniform thickness and distinct permeability. The cavity is subjected to differential heating from the vertical walls. The results obtained are used to further evaluate the capacity of the lumped-system analysis in the prediction of heat transfer results of layered porous cavities. It has been found that predictions by the lumped-system model are reasonably good for the range of Rayleigh numbers encountered in engineering applications. In addition, the predictions improve when the number of sublayers increases as well as the sublayer thickness becomes more uniform. Thus, it proves that the lumped-system analysis can offer a quick estimate of heat transfer result from a layered porous cavity with reasonable accuracy.

Study on the Behaviors of a Conceptual Passive Containment Cooling System

2013 ◽  
Author(s):  
Jianjun Wang ◽  
Beibei Luo ◽  
Xueqing Guo ◽  
Zhongning Sun
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
System Analysis ◽  
Cooling System ◽  
Severe Accident ◽  
Fixed Temperature ◽  
Term Operation ◽  
The Heat Transfer Coefficient ◽  
Containment Integrity

In this paper, a closed loop concept, which is composed of two heat exchangers with same scale, pipes, valves and one tank, has been developed as a passive containment cooling system for a large dry concrete containment. The system is designed to maintain the containment integrity by taking the heat drained into the containment following a severe accident, e.g. LOCA or MSLB. Under different conditions in containment, the system may operate in single phase mode or two phase mode. According to the design limitation of containment, the fixed temperature boundary condition is applied to the system analysis. We have developed the codes for the analysis of the system by ourselves. The operating behaviors of the system are studied numerically from startup to long term operation. In the light of the fact that the fraction of steam in the containment may be changing during the accident scenario, it is reasonable that the heat transfer coefficient will be different. Therefore, the sensitivity analysis of the heat transfer coefficient is also performed. Based on the results and corresponding analysis, it can be concluded that the system may be utilized to meet the design purpose for the containment integrity requirement.

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