scholarly journals Applicability of heat-exchanger theory to estimate heat losses to surrounding formations in a thermal flood

2019 ◽  
Vol 10 (4) ◽  
pp. 1565-1574
Author(s):  
Kazeem A. Lawal
Keyword(s):  
Heat Exchanger ◽  
Heat Transport ◽  
Petroleum Reservoirs ◽  
Heat Losses ◽  
Petroleum Reservoir ◽  
Field Scale ◽  
Proposed Model ◽  
The Subject ◽  
Rate Of Heating ◽  
Infinite Reservoir

Abstract Heat losses to cap and base rocks undermine the performance of a thermal flood. As a contribution to this subject, this paper investigates the applicability of the principles of heat exchanger to characterise heat losses between a petroleum reservoir and the adjacent geologic systems. The reservoir-boundary interface is conceptualised as a conductive wall through which the reservoir and adjacent formations exchange heat, but not mass. For a conduction-dominated process, the heat-transport equations are formulated and solved for both adiabatic and non-adiabatic conditions. Simulations performed on a field-scale example show that the rate of heating a petroleum reservoir is sensitive to the type of fluids saturating the adjoining geologic systems, as well as the characteristics of the cap and base rocks of the subject reservoir. Adiabatic and semi-infinite reservoir assumptions are found to be poor approximations for the examples presented. Validation of the proposed model against an existing model was satisfactory; however, remaining differences in performances are rationalised. Besides demonstrating the applicability of heat-exchanger theory to describe thermal losses in petroleum reservoirs, a novelty of this work is that it explicitly accounts for the effects of the reservoir-overburden and reservoir-underburden interfaces, as well as the characteristics of the fluid in the adjacent strata on reservoir heating. These and other findings should aid the design and management of thermal floods.

СУБ’ЄКТ-ОРІЄНТОВАНА МОДЕЛЬ ПСИХОКОРЕКЦІЇ ГІПЕРАКТИВНОСТІ ДОШКІЛЬНИКІВ

1970 ◽  
Vol 7 (1) ◽  
pp. 70-79
Author(s):  
Людмила Прокопів
Keyword(s):  
Psychosocial Development ◽  
Special Educational Needs ◽  
Hyperactivity Disorder ◽  
Complex Approach ◽  
Proposed Model ◽  
Special Programs ◽  
Developmental Impairment ◽  
The Subject ◽  
Comprehensive Programs ◽  
Theoretical Foundations

У статті визначено актуальність та необхідність розробки і впровадження сучасних комплексних програм психологічної корекції для дошкільників з гіперактивним розладом і дефіцитом уваги (ГРДУ). Підкреслено неможливість надання ефективної допомоги дітям з ГРДУ без урахування їх особливих потреб, пов’язаних з освітою. Обґрунтовано теоретичні засади суб’єкт-орієнтованої моделі психокорекції гіперактивності дошкільників шляхом синтезу патогенетичного і психолого-педагогічного підходів на базі принципу інтегральної суб’єктності З. С. Карпенко. Запропонована модель психокорекції гіперактивності пояснює гальмування і деформацію психосоціального розвитку дошкільника затримкою розвитку його суб’єктності в сенсомоторному, атенціональному, мнемічному, афективно-конативному, мовленнєвому, комунікативному аспектах. Аргументовано необхідність здійснення комплексного підходу до психологічної корекції, виховання і навчання гіперактивних дошкільників і впровадження спеціальних програм психоедукації для батьків. The paper highlights the topicality and need for elaboration and implementation of up-to-date comprehensive programs of psychological correction for preschool children with Attention Deficit/Hyperactivity Disorder (ADHD). Failure to provide effective aid for children with ADHD without regard to their special educational needs has been underlined. Theoretical foundations of the subject-oriented model of psychocorrection of preschool children’s hyperactivity by means of synthesis of pathogenic and psychological-pedagogical approaches on the basis of Z. S. Karpenko’s principle of integral subjectivity have been validated. The proposed model of psychocorrection of hyperactivity explains developmental impairment and deformation of psychosocial development of preschoolers by a delay of their subjectivity in terms of sensomotor, attentional, mnemic, affective-conative, speech and communicative aspects. The need for actualization of a complex approach towards psychological correction, upbringing and education of hyperactive preschoolers and implementation of special programs of psychological education for parents has been reasoned.

scholarly journals Numerical and experimental investigation of alumina-based nanofluid effects on double-pipe heat exchanger thermal performances

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
A. Bendaraa ◽  
My. M. Charafi ◽  
A. Hasnaoui
Keyword(s):  
Heat Exchanger ◽  
Volume Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Deionized Water ◽  
Comsol Multiphysics ◽  
Exchange Coefficient ◽  
The Subject ◽  
Double Pipe ◽  
Pipe Heat ◽  
Thermoelectric Power Plant

AbstractIn this study, we investigate the thermal behaviour of nanofluids in a double-pipe heat exchanger. It is about a counterflow configuration, designed to cool a lubrication unit of a thermoelectric power plant. The subject of this work is to evaluate the thermal performances of the exchanger by using a nanofluid based on alumina suspension comparing with deionized water. In order to evaluate the thermal performance of the studied configuration, we carried out numerical experiments in an application developed on COMSOL Multiphysics environment, these experiments are utilized to show the feasibility of this application. As result, we found that the nanofluid with an increase in its volume fraction leads to an increase in the overall exchange coefficient, the convective heat transfer coefficient, as well as the efficiency and the power of the exchanger. It is noted that an increase of 1% in volume fraction, can enhance the overall exchange coefficient, the power and the effectiveness of the exchanger by 17.62%, 1.473% and 10.80% respectively. Besides, it is noted that the increase in the concentration of nanofluids leads to a narrowing of the pinch points of the inlet and outlet temperatures, which means that nanofluids are more efficient in cooling temperatures than conventional fluids.

scholarly journals Estimating evapotranspiration using the complementary relationship and the Budyko framework

2017 ◽  
Vol 8 (4) ◽  
pp. 771-790 ◽  
Author(s):  
Homin Kim ◽  
Jagath J. Kaluarachchi
Keyword(s):  
Root Mean Square Error ◽  
Vegetation Cover ◽  
Meteorological Data ◽  
Mean Square ◽  
Limited Data ◽  
Complementary Relationship ◽  
Proposed Model ◽  
The Usa ◽  
Dry Conditions ◽  
The Subject

Abstract Several models have been developed to estimate evapotranspiration. Among those, the complementary relationship has been the subject of many recent studies because it relies on meteorological data only. Recently, the modified Granger and Gray (GG) model showed its applicability across 34 diverse global sites. While the modified GG model showed better performances compared to the recently published studies, it can be improved for dry conditions and the relative evaporation parameter in the original GG model needs to be further investigated. This parameter was empirically derived from limited data from wet environments in Canada – a possible reason for decreasing performance with dry conditions. This study proposed a refined GG model to overcome the limitation using the Budyko framework and vegetation cover to describe relative evaporation. This study used 75 eddy covariance sites in the USA from AmeriFlux, representing 36 dry and 39 wet sites. The proposed model produced better results with decreasing monthly mean root mean square error of about 30% for dry sites and 15% for wet sites compared to the modified GG model. The proposed model in this study maintains the characteristics of the Budyko framework and the complementary relationship and produced improved evapotranspiration estimates under dry conditions.

scholarly journals Policy Assessment Investment Appeal of Innovation Projects Enterprises

2019 ◽  
Vol 9 (2) ◽  
pp. 5111-5122
Keyword(s):  
Regression Analysis ◽  
Practical Experience ◽  
Cash Flows ◽  
Financial Indicators ◽  
Correlation And Regression Analysis ◽  
Proposed Model ◽  
Modern Economic ◽  
The Subject ◽  
The Relationship ◽  
Future Cash Flows

The aim of the article is to summarize theoretical principles and practical experience regarding the relationship between the investment attractiveness of innovative projects and economic growth. The methods of correlation and regression analysis, extrapolation and modeling are used. The subject of the study was the features and patterns of the formation, use and regulation of the policy for assessing the investment attractiveness of company’s innovative projects in modern economic conditions. In the course of the study, an algorithm was developed to assess the size and level of investment attractiveness of the algorithm is based on the allocation of components of the enterprise’s potential. It is indicated that models for evaluating efficiency and cost should take into account not only future cash flows, but also non-financial indicators. Are proposed the construction of a multivariate model based on regression analysis. The essence of this model is to combine the traditional method of correlation analysis with least squares. This approach has the main advantage - relatively high accuracy and low costs in the construction and forecasting. The proposed model of a system for ensuring the investment attractiveness of innovative projects of companies consists of two main subsystems - information-analytical and implementation-control. These blocks provide results that allow you to increase investment attractiveness, as well as timely determine the external and internal risks of the enterpriseThe aim of the article is to summarize theoretical principles and practical experience regarding the relationship between the investment attractiveness of innovative projects and economic growth. The methods of correlation and regression analysis, extrapolation and modeling are used. The subject of the study was the features and patterns of the formation, use and regulation of the policy for assessing the investment attractiveness of company’s innovative projects in modern economic conditions. In the course of the study, an algorithm was developed to assess the size and level of investment attractiveness of the algorithm is based on the allocation of components of the enterprise’s potential. It is indicated that models for evaluating efficiency and cost should take into account not only future cash flows, but also non-financial indicators. Are proposed the construction of a multivariate model based on regression analysis. The essence of this model is to combine the traditional method of correlation analysis with least squares. This approach has the main advantage - relatively high accuracy and low costs in the construction and forecasting. The proposed model of a system for ensuring the investment attractiveness of innovative projects of companies consists of two main subsystems - information-analytical and implementation-control. These blocks provide results that allow you to increase investment attractiveness, as well as timely determine the external and internal risks of the enterprise

scholarly journals The Safety of Professionalization Subjects in Psychological and Neuropsychological Aspects

2021 ◽  
Vol 12 (1) ◽  
pp. 19-39
Author(s):  
Olha Lazorko ◽  
Virna Zhanna ◽  
Vasyl Yahupov ◽  
Oksana Valchuk-Orkusha ◽  
Iryna Melnyk ◽  
...  
Keyword(s):  
Professional Training ◽  
Functional Organization ◽  
Personal Characteristics ◽  
Personal Protection ◽  
Proposed Model ◽  
Security Problem ◽  
The Subject ◽  
Methodological Principles ◽  
The Individual ◽  
Graduating Students

Recently, the revision of priorities in the interpretation of the security problem and their transformation from the interests of the state to the interests of man himself, have actualized the study of psychological protection. Especially aspects of personal protection are relevant in the professional sphere, which led to the development of the problem of personal protection as a subject of professionalization, taking into account psychological and neuropsychological factors. The purpose of the study is to empirically verify the structurally functional organization of personal protection as a subject of professionalization. The proposed model is based on the methodological principles and conditions of the content of the subject, system and synergetic approaches (the subject principle determines the subjective features expressed in subjective-personal characteristics, the system principle - substantial features expressed in socially personal characteristics; the synergetic principle - quality features that are integrative sign of professional protection of the individual. The sample of the study was: graduating students (n = 180); 4th and 5th year students (n = 230); doctors and medical workers (n = 441). The characteristics of psychodiagnostic tools used in these blocks of the empirical research program are described. The results of the study demonstrated the excellent content of empirical referents of professional protection of the individual in the period of professional optation, professional training and actual professional implementation in ordinary and special conditions of activity. The scientific position of the empirical study of professional safety of the individual is realized in the separation of the experience of social satisfaction, the system-forming factor of which is the urgent need that initiates the manifestation of successful professional realization.

scholarly journals Evaluation of Alternative Designs for a High Temperature Particle-to-sCO2 Heat Exchanger

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Clifford K. Ho ◽  
Matthew Carlson ◽  
Kevin J. Albrecht ◽  
Zhiwen Ma ◽  
Sheldon Jeter ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Structural Reliability ◽  
Packed Bed ◽  
Heat Losses ◽  
Transient Operation

This paper presents an evaluation of alternative particle heat-exchanger designs, including moving packed-bed and fluidized-bed designs, for high-temperature heating of a solar-driven supercritical CO2 (sCO2) Brayton power cycle. The design requirements for high pressure (≥20 MPa) and high temperature (≥700 °C) operation associated with sCO2 posed several challenges requiring high-strength materials for piping and/or diffusion bonding for plates. Designs from several vendors for a 100 kW-thermal particle-to-sCO2 heat exchanger were evaluated as part of this project. Cost, heat-transfer coefficient, structural reliability, manufacturability, parasitics and heat losses, scalability, compatibility, erosion and corrosion, transient operation, and inspection ease were considered in the evaluation. An analytic hierarchy process was used to weight and compare the criteria for the different design options. The fluidized-bed design fared the best on heat transfer coefficient, structural reliability, scalability, and inspection ease, while the moving packed-bed designs fared the best on cost, parasitics and heat losses, manufacturability, compatibility, erosion and corrosion, and transient operation. A 100 kWt shell-and-plate design was ultimately selected for construction and integration with Sandia's falling particle receiver system.

scholarly journals Comparative analysis of selected glass systems by dynamic simulation using measured real environmental conditions

2020 ◽  
Vol 172 ◽  
pp. 19009
Author(s):  
Silvia Bizoňová ◽  
Dušan Katunský ◽  
Miloslav Bagoňa
Keyword(s):  
Dynamic Simulation ◽  
Energy Savings ◽  
Building Envelope ◽  
Heat Losses ◽  
Experimental Glass ◽  
Existing Structures ◽  
Spectrally Selective ◽  
The Subject ◽  
Simulation Results ◽  
Made In

The subject of the study presents the measurement of temperatures on surfaces of glass systems of existing structures and the surfaces of experimental glass systems obtained by dynamic simulation. Measurements were made in the test cells of the Faculty of Civil Engineering of the Technical University of Košice. The partial results of which are the basis for the comparison of the currently installed and experimentally designed glass systems using spectrally selective films. The proposed mathematical-physical model was simplified by replacing the sash, frame and its components with a homogenous element with minimal shape modifications, while this does not have a significant effect on the simulation results. The choice of the proposed glass system respects the need for reduction of solar gains in summer and heat losses in buildings in winter through the weakest part of the building envelope and indicates future energy savings in relation to cooling and heating costs with a view to optimizing light and thermal comfort.

The Potential Danger of Fire in Gas Turbine Heat Exchangers

1969 ◽  
Author(s):  
C. F. McDonald
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Engine Operation ◽  
Exhaust Heat ◽  
The Subject ◽  
Gas Turbine Cycle

Increased emphasis is being placed on the regenerative gas turbine cycle, and the utilization of waste heat recovery systems, for improved thermal efficiency. For such systems there are modes of engine operation, where it is possible for a metal fire to occur in the exhaust heat exchanger. This paper is intended as an introduction to the subject, more from an engineering, than metallurgical standpoint, and includes a description of a series of simple tests to acquire an understanding of the problem for a particular application. Some engine operational procedures, and design features, aimed at minimizing the costly and dangerous occurrence of gas turbine heat exchanger fires, are briefly mentioned.

A Mesoscopic Damage Model for Predicting the Plastic-Creep Life of Welded Joints Subjected to Quasi-Static Loading

2010 ◽  
Author(s):  
Khosrow Zarrabi ◽  
Jad Jelwan ◽  
Tahir Mahmood
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Damage Model ◽  
Life Assessment ◽  
Research Activities ◽  
Proposed Model ◽  
Engineering Problems ◽  
Complex Engineering ◽  
The Subject ◽  
Plastic Creep

The integrity and life assessment of welded joints operating at high temperatures and subjected to non-linear damage mechanisms such as plasticity and creep are complex engineering problems and currently the subject of intensive research activities. This paper gauges the accuracy of a model that takes into account creep and plasticity deformation proposed by Zarrabi et al. to a butt welded thick tube. It is shown that the proposed model can predict the life of this welded joint with an error of 1%. Currently the model is being extended to include fatigue deformation.

Sign in / Sign up

Export Citation Format

Share Document