scholarly journals MEASURING TEMPERATURE OF THE MEDIUM OF SHIP COMPRESSOR PIPING USING TEMPERATURE OF THE OUTER WALL

2018 ◽  
pp. 81-86
Author(s):  
Alexander Evgenyevich Semenov ◽  
Sergey Anatolyevich Putilin
Keyword(s):  
Heat Transfer ◽  
Theoretical Data ◽  
Outer Wall ◽  
Operating Conditions ◽  
Measured Temperature ◽  
Medium Temperature ◽  
Factors Affecting ◽  
Operating Modes ◽  
Piping Systems ◽  
Pipeline Wall

To determine the temperature of the medium in the ship's piping systems there are used readings of contact thermometers, pyrometers and thermal scans which measure the temperature of the pipeline rather accurately. Aside from corrections for accuracy of the measurement of the wall temperature, it is necessary to move towards measuring temperature of the medium. Readings of the temperature of the pipeline wall differ from the readings of the medium temperature inside the pipeline, so it is necessary to calculate and find the temperature of the medium in the pipeline. After solving a system of equations describing the phenomenon of heat transfer through the cylindrical surface, there has been worked out the technique of measuring temperature of the pipeline medium, according to the measured temperature of the pipe wall. The conditions of heat transfer can vary for different pipelines and media. The paper gives calculated temperature corrections for different operating conditions of the pipeline. To carry out calculations, a computer program has been written in the Mathcad mathematical package. Temperature corrections have been calculated to determine the medium temperature inside the pipeline using the temperature value of the outer wall of the pipeline. There has been carried out analysis of various factors affecting temperature changes: heat transfer to the air, heat transfer of medium inside the pipeline, wall thickness and contamination. Verification of theoretical data has been made on a ship of the compressor unit. The experiment confirmed the possibility of measuring temperature of the medium inside the pipeline, according to the temperature of pipeline surface using the developed corrections. Devices measuring the temperature of the pipeline walls can be used as additional measurement to enhance informativeness of testing results, analysis of operating modes, and improve the operation reliability of ship piping systems

scholarly journals THERMAL MODEL OF THE "INDUCTION GENERATOR–INDUCTION MOTOR" SYSTEM WITH NON–SYMMETRY IN THE STATOR WINDINGS

2021 ◽  
Vol 2 (53) ◽  
pp. 47-55
Author(s):  
V. Chenchevoi ◽  
◽  
Iu. Zachepa ◽  
O. Chornyi ◽  
R. Yatsiuk ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Thermal State ◽  
Asynchronous Motor ◽  
Operating Conditions ◽  
Factors Affecting ◽  
Thermal Transients ◽  
Operating Modes ◽  
Stator Windings ◽  
Asynchronous Generator

Purpose. Development of the IG model for estimation of influence of variations of parameters of the generator on quality of process of self–excitation at definition of the basic and boundary operating modes and system of initial excitation at invariable parameters of the generator. Result. The article presents studies of the system "asynchronous generator-asynchronous motor" with parametric asymmetry to determine the quality of generated electricity in load modes of operation on a mathematical model. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an asynchronous electric motor from an autonomous power source based on an asynchronous generator. On a thermal mathematical model, a study of the influence of the asymmetry of the output voltage and its deviation from the nominal value on the heating of the connected asynchronous motor was carried out. A regression model has been developed for studying the operating conditions of electricity consumers when powered by an asynchronous generator with an asymmetry of the stator windings. Practical value. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of asynchronous machines, at which they will not overheat in excess of the maximum permissible temperature values of the corresponding insulation classes. Figures 9, tables 2, references 23.

Modeling of Heat Transfer in a Moving Packed Bed: Case of the Preheater in Nickel Carbonyl Process

2005 ◽  
Vol 73 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Redhouane Henda ◽  
Daniel J. Falcioni
Keyword(s):  
Heat Transfer ◽  
Packed Bed ◽  
Outer Wall ◽  
Volume Averaging ◽  
Equation Model ◽  
Operating Conditions ◽  
Design Parameters ◽  
Gas Phases ◽  
Calculation Results ◽  
The Difference

Heat transfer in a two-dimensional moving packed bed consisting of pellets surrounded by a gaseous atmosphere is numerically investigated. The governing equations are formulated based on the volume averaging method. A two-equation model, representing the solid and gas phases separately, and a one-equation model, representing both the solid and gas phases, are considered. The models take the form of partial differential equations with a set of boundary conditions, some of which were determined experimentally, and design parameters in addition to the operating conditions. We examine and discuss the parameters in order to reduce temperature differences from pellet to pellet. The calculation results show that by adopting a constant temperature along the preheater outer wall and decreasing the velocity of the pellets in the preheater, the difference in temperature from pellet to pellet is reduced from ∼120°C to ∼55°C, and the thermal efficiency of the preheater is tremendously improved.

Investigation of Circumferential Variation of Heat Transfer Coefficients During In-Tube Evaporation for R-22 and R-407C Using Liquid Crystal

2002 ◽  
Vol 124 (5) ◽  
pp. 845-853 ◽  
Author(s):  
Seok Ho Yoon ◽  
Min Soo Kim
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Cross Sections ◽  
Outer Wall ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Measured Temperature ◽  
Thermochromic Liquid Crystal ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Heat transfer coefficients during evaporation in a horizontal smooth tube for R-22 and R-407C (R-32/125/134a, 23/25/52 wt.%) have been measured using thermochromic liquid crystal. Focus has been put on the circumferential variation of heat transfer coefficients at several cross-sections of the test tube with inner diameter of 11.3 mm for several vapor qualities of refrigerant. The inner wall temperatures were calculated by one dimensional heat conduction equation from the measured outer wall temperatures, which were obtained using an image processing technique with thermochromic liquid crystal (TLC). The relation between measured temperature and color information (Red-Green-Blue values) of thermochromic liquid crystal was calibrated by a neural network method. Results show that circumferential variation of heat transfer coefficients for R-22 is quite large with the highest heat transfer coefficient at the top of the tube. For zeotropic mixture of R-407C, similar trend has been observed with less difference between the heat transfer coefficients at the top and bottom than that of R-22.

scholarly journals OPTIMAL CONTROL OF THE TRACTOR MOVEMENT

2020 ◽  
Author(s):  
E. Kalinin ◽  
◽  
M. Myasushka
Keyword(s):  
Optimal Control ◽  
Travel Speed ◽  
Gear Ratio ◽  
Operating Conditions ◽  
Design Parameters ◽  
Logic Device ◽  
Factors Affecting ◽  
Operating Modes ◽  
Methods Analytical ◽  
The Right

Goal of the study. Assessment of the possibility of optimizing tractor control by methods of automatic search for the optimum point. To achieve this goal, you must complete the following tasks: – to analyze the operating conditions of the tractor unit with the determination of the force factors affecting its operating conditions; – to develop a scheme and algorithm for the operation of the extreme regulator and analyze its functioning. Research methods. Analytical studies are based on methods of optimization of power factors acting on a tractor. The results of the study. An automatic regulator is considered, which provides an optimal ratio of the engine speed and the transmission gear ratio for each speed. The logic device generates a signal to change the power train ratio. The required travel speed of the tractor unit is set by the operator using the speed regulator. Changing the gear ratio changes the speed of the tractor. The signal of the deviation of the speed of movement, after amplification, provides an effect on the fuel supply and, by changing the revolutions of the crankshaft of the engine, brings the actual speed of the tractor to the set one. In the control system, the measurement of the amount of fuel consumed by the engine is carried out by a flow meter, and the measurement is carried out at certain intervals, and the current value is compared with the previous one. Reducing fuel consumption means that the influence on the change in gear ratio has been chosen in the right direction. Conclusions. The paper proposes a self-adjusting system. In a theoretical study of the possibility of optimal control of the tractor movement, equations are determined that are easily solved by the graphical analytical method. The graphical plotting determines the time the system reaches the optimal mode. The considered example of regulation of the power drive and the tractor engine does not exhaust the scope of application of self-adjusting systems. The operating modes of a number of units, as well as some interrelationships of design parameters, have static characteristics that ensure widespread use of these systems.

Natural Convection From a Tube Bundle in a Thin Inclined Enclosure

2004 ◽  
Vol 126 (2) ◽  
pp. 702-709 ◽  
Author(s):  
W. Liu ◽  
J. H. Davidson ◽  
F. A. Kulacki
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Tube Bundle ◽  
Convection Heat Transfer ◽  
Constant Heat Flux ◽  
Working Fluid ◽  
Measured Temperature ◽  
Transfer Coefficients ◽  
Rectangular Array ◽  
Operating Modes

Natural convection heat transfer coefficients for a rectangular array of eight tubes contained in a thin enclosure of aspect ratio 9.3:1 and inclined at 30 deg to the horizontal are measured for a range of transient operating modes typical of a load side heat exchanger in unpressurized integral collector-storage systems. Water is the working fluid, and thermal charging is accomplished via a constant heat flux on the upper boundary. All other boundaries are well insulated. Results for isothermal and stratified enclosures yield the following correlation for the overall Nusselt number: NuD=0.728±0.002RaD0.25,4.0×105⩽RaD⩽1.4×107. The flow field in the enclosure is inferred from measured temperature distributions. The temperature difference that drives natural convection is also determined. The results extend earlier work for the case of a single tube and provide limiting case heat transfer data for a tube bundle that occupies the upper portion of the collector storage.

scholarly journals Augmentation of Fluid Flow and Heat Transfer Characteristics in corrugated Channel: A Review Study

2021 ◽  
Vol 14 (1) ◽  
pp. 31-56
Author(s):  
Hayder Jaffal
Keyword(s):  
Heat Transfer ◽  
Operating Conditions ◽  
Geometrical Parameters ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Factors Affecting ◽  
Flow And Heat Transfer ◽  
Trapezoidal Shape ◽  
Thermal Improvement ◽  
Review Study

The corrugation configuration played an important role in heat transfer enhancement in many engineering applications such as heat exchangers, microchannel heat sink, solar collectors, etc. The significance of the corrugation configuration is manifested in its ability to offer a larger heat transfer area more than a straight channel. Besides, the periodic interruption and redeveloping of the thermal boundary layer which is an important feature offered by corrugation is remarkably enhanced the heat transfer. The researchers were keen to take advantage of these features and develop them by manipulating geometrical parameters to obtain the optimal results. The current work aims to collect available research data, which focused on improving heat transfer in corrugated channels and identifying the most important factors affecting the performance of corrugated channels. Among the studied shapes of the various operating conditions of the corrugated channels, the researchers unanimously agreed that the trapezoidal shape of the corrugations gives the best thermal improvement with a reasonable pressure drop inside the channels.

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

DIESEL ENGINE OPERATION IN USE OF FUEL WITH ADDITIVES

2018 ◽  
pp. 18-24
Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Combustion Engines ◽  
Engine Operation ◽  
Factors Affecting ◽  
Operating Modes ◽  
Positive Effects

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.

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