Efficiencies, Thermodynamics and the By-Pass Engine

1963 ◽  
Vol 67 (636) ◽  
pp. 796-796
Author(s):  
H. Pearson
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Exchange Process ◽  
Thermodynamic Cycle ◽  
Point Of View ◽  
Propulsive Efficiency ◽  
Heat Exchange Process ◽  
The Subject ◽  
Cycle Efficiency ◽  
Jet Velocities

I Think Mr. Filleul's main point, (in the November Journal) somewhat hidden behind some obscure comments about Carnot engines and the like, is that in a by-pass engine with heat exchanger, the heat exchange process is making a definite alteration to the thermodynamic cycle efficiency of the whole engine and not just changing the propulsive efficiency. This may or may not be an important point, depending upon the point of view of the expositor of the subject. In fact, even without heat exchange and when the by-pass compressor and turbine have realistic efficiencies, the by-pass process itself does alter in an unfavourable direction the overall thermodynamic cycle efficiency. This is one reason why in a by-pass compressor with separate jets one does not wish to make for optimum performance the by-pass and jet velocities equal.

COMPUTER SIMULATION OF FLOW IN CORRUGATED CHANNEL OF PLATE HEAT EXCHANGER

2020 ◽  
pp. 51-58
Author(s):  
Л. А. Кущев ◽  
В. Н. Мелькумов ◽  
Н. Ю. Саввин
Keyword(s):  
Computer Simulation ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
High Speed ◽  
Exchange Process ◽  
Plate Heat Exchanger ◽  
System Stability ◽  
Plate Heat ◽  
Corrugated Channel ◽  
Heat Exchange Process

Постановка задачи. Рассматривается теплообменный процесс, протекающий в модифицированном гофрированном межпластинном канале интенсифицированного пластинчатого теплообменного аппарата с повышенной турбулизацией теплоносителя. Необходимо разработать компьютерную модель движения теплоносителя в диапазоне скоростей 0,1-1,5 м/с и определить коэффициент турбулизации пластинчатого теплообменника. Результаты. Приведены результаты компьютерного моделирования движения теплоносителя в межпластинном гофрированном канале оригинального пластинчатого теплообменного аппарата с помощью программного комплекса Аnsys . Определены критерии устойчивости системы. Выполнено 3 D -моделирование канала, образуемого гофрированными пластинами. При исследовании процесса турбулизации были рассмотрены несколько скоростных режимов движения теплоносителя. Определен коэффициент турбулизации Tu, %. Выводы. В результате компьютерного моделирования установлено увеличение коэффициента теплопередачи К, Вт/(м ℃ ) за счет повышенной турбулизации потока, что приводит к снижению металлоемкости и уменьшению стоимости теплообменного оборудования. Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1-1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined. Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.

scholarly journals COMPUTER SIMULATION OF FLOW IN CORRUGATED CHANNEL OF PLATE HEAT EXCHANGER

2021 ◽  
pp. 45-53
Author(s):  
L. A. Kushchev ◽  
V. N. Melkumov ◽  
N. Yu. Savvin
Keyword(s):  
Computer Simulation ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
High Speed ◽  
Exchange Process ◽  
Plate Heat Exchanger ◽  
System Stability ◽  
Plate Heat ◽  
Corrugated Channel ◽  
Heat Exchange Process

Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1--1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined.Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m2 ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.

scholarly journals Mathematical modeling of non-steady heat exchange process in cryogenic coil-wound heat exchangers

2020 ◽  
Vol 324 ◽  
pp. 01009
Author(s):  
Aleksandr A. Vorob’ev ◽  
Dmitriy P. Posanchukov ◽  
Aleksandr A. Kozlov ◽  
Aleksey V. Ivanov
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Exchange Process ◽  
Air Separation ◽  
Separation Unit ◽  
Finned Tubes ◽  
Air Separation Unit ◽  
Heat Exchange Process ◽  
Steady Heat

The paper discusses a dynamic model of coil-wound heat exchanger and its implementation in the MathWorks SimulinkTM computer simulation system. As a simulation object was chosen a coil-wound heat exchanger with wire-finned tubes of a commercial low-capacity air separation unit. The methods for obtaining experimental data has been described, the non-steady heat exchange process has been simulated, and the obtained results have been analyzed.

The Second Law Quality of Energy Transformation in a Heat Exchanger

1990 ◽  
Vol 112 (2) ◽  
pp. 295-300 ◽  
Author(s):  
D. P. Sekulic
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Entropy Generation ◽  
Exchange Process ◽  
Quantitative Measure ◽  
Inlet Temperature ◽  
Energy Transformation ◽  
Two Fluids ◽  
Heat Exchange Process

This paper presents the entropy generation (irreversibility) concept as a convenient method for estimating the quality of the heat exchange process in heat exchanger analysis. The entropy generation caused by finite temperature differences, scaled by the maximum possible entropy generation that can exist in an open system with two fluids, is used as the quantitative measure of the quality of energy transformation (the heat exchange process). This measure is applied to a two-fluid heat exchanger of arbitrary flow arrangement. The influence of different parameters (inlet temperature ratio, fluid flow heat capacity rate ratio, flow arrangements) and the heat exchanger thermal size (number of heat transfer units) on the quality of energy transformation for different types of heat exchangers is discussed. In this analysis it is assumed that the contribution of fluid friction to entropy generation is negligible.

scholarly journals Influence of circulating pump efficiency on the heat exchange process in a plate heat exchanger used in a solar heating installation

2020 ◽  
Vol 154 ◽  
pp. 05008
Author(s):  
Paweł Obstawski ◽  
Tomasz Bakoń ◽  
Anna Kozikowska
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Exchange Process ◽  
Plate Heat Exchanger ◽  
Solar Heating ◽  
Pump Efficiency ◽  
Plate Heat ◽  
Heating Installation ◽  
Heat Exchange Process ◽  
Secondary Side

In solar heating systems with an absorber area of more than 20 m2, a plate heat exchanger is used as a separator between the primary glycol-based refrigerant and secondary water. The use of a plate heat exchanger enables an increase in the heat exchange area compared to the standard coil heat exchangers located inside the domestic hot water tank. An important problem is to determine the volume flow rate on both the primary and secondary side of the exchanger. The paper presents an analysis of the influence of the circulation pump efficiency on the primary and secondary side of the heat exchanger installed in a solar heating installation on the intensity of the heat exchange process.

scholarly journals Multi-criterion parameters optimization of the heat exchanger element air heating system of a building

2018 ◽  
Vol 251 ◽  
pp. 03001
Author(s):  
Andrei Melekhin
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Exchange Process ◽  
Heating System ◽  
Parameters Optimization ◽  
Heat Output ◽  
Maximum Heat ◽  
Air Heating ◽  
Heat Exchange Process

Air heating systems of buildings are resource-consuming systems, for this reason, improving their resource efficiency appears to be of great significance. The author have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger engineering systems of buildings, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model. Finding the best managed of the parameters of the heat exchanger element air heating system of a building is possible with the developed by the author of a comprehensive method of research based on multi-criteria parameters optimization with the introduction of empirically obtained data.

Research and Develop on Series of Cryogenic Liquid Nitrogen Coil-Wound Heat Exchanger

2014 ◽  
Vol 1070-1072 ◽  
pp. 1817-1822
Author(s):  
Zhou Wei Zhang ◽  
Ya Hong Wang ◽  
Jia Xing Xue
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Liquid Nitrogen ◽  
Heat Exchangers ◽  
Exchange Process ◽  
Cryogenic Liquid ◽  
Gas Purification ◽  
Important Research ◽  
Research Directions ◽  
Heat Exchange Process

The research and development situation of liquid nitrogen coil-wound heat exchanger were discussed in view of heat exchange in gas purification field in petrol-chemical industry. The basic designing methods and the multi-stream heat exchange process were illustrated by the cryogenic and high pressure crossing heat exchange equipments of liquid nitrogen coil-wound heat exchanger with multi-stream and multiphase flow, including Three-stream back-cooling heat exchangerin first stage, Four-stream back-cooling heat exchangerin second stage, Five-stream back-cooling heat exchangerin third stage, Multi-stream main back-coolingcoil-wound heat exchanger etc. A series of coil-wound heat exchangers with different mixed fluids and different applications were described. The winding structure characteristics and the work principles of the spiral pipe bundles were elaborated to give references for the scientific design and calculation of coil-wound heat exchanger in cryogenic field. The important research directions and the critical scientific problems were forecasted.

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