scholarly journals Modelling of Heat Transfer Processes in Heat Exchangers for Cardiopulmonary Bypass

Mathematics ◽  
2021 ◽  
Vol 9 (23) ◽  
pp. 3125
Author(s):  
Valentyna Danilova ◽  
Vladyslav Shlykov ◽  
Vitalii Kotovskyi ◽  
Nikolaj Višniakov ◽  
Andžela Šešok
Keyword(s):  
Cardiopulmonary Bypass ◽  
Heat Exchanger ◽  
Temperature Control ◽  
Exchange Process ◽  
Control Device ◽  
Control Circuit ◽  
Design Stage ◽  
Controlled Cooling ◽  
Heat Exchange Process ◽  
The Creation

A model of the heat exchange process in the heat exchanger of the cardiopulmonary bypass device is proposed which allows for automation of the process of temperature regulation in the cardiopulmonary bypass with an accuracy of ±1 °C during cardiac surgery under controlled cooling and warming of the patient’s heart and brain. The purpose of this research is to create a concept and model of the temperature control circuit using the MSC Easy5 system, the creation of mathematical models of blocks of the temperature control circuit, and the description of the principle of temperature control in the cardiopulmonary bypass circuit. The model of the temperature control loop in the heat exchanger of the heart-lung machine was created using the MSC Easy5 system with a programmable microcontroller. The microcontroller implements a specialized temperature control algorithm in the C language. The model allows the creation of a full-fledged virtual prototype of a temperature control device in a heat exchanger, and helps to conduct virtual tests of the developed device at the design stage. The model identifies control system flaws and influences decisions made before producing an official prototype of the product.

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.

First and Second Law Analysis of Radical Intercooling Concepts

2017 ◽  
Author(s):  
Oskar Thulin ◽  
Olivier Petit ◽  
Carlos Xisto ◽  
Xin Zhao ◽  
Tomas Grönstedt
Keyword(s):  
Heat Exchanger ◽  
Exchange Process ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Aircraft Engine ◽  
Comparison Results ◽  
Useful Power ◽  
Heat Exchange Process ◽  
Detailed Assessment ◽  
Closed Systems

An exergy framework was developed taking into consideration a detailed analysis of the heat exchanger (intercooler) component irreversibilities. Moreover, it was further extended to include an adequate formulation for closed systems, e.g. a secondary cycle, moving with the aircraft. Afterwards the proposed framework was employed to study two radical intercooling concepts. The first proposed concept uses already available wetted surfaces, i.e. nacelle surfaces, to reject the core heat and contribute to an overall drag reduction. The second concept uses the rejected core heat to power a secondary organic Rankine cycle and produces useful power to the aircraft-engine system. Both radical concepts are integrated into a high bypass ratio turbofan engine, with technology levels assumed to be available by year 2025. A reference intercooled cycle incorporating a heat exchanger in the bypass duct is established for comparison. Results indicate that the radical intercooling concepts studied in this paper show similar performance levels to the reference cycle. This is mainly due to higher irreversibility rates created during the heat exchange process. A detailed assessment of the irreversibility contributors, including the considered heat exchangers and the secondary cycle major components is made. A striking strength of the present analysis is the assessment of the component irreversibility rate and its contribution to the overall aero-engine losses.

Stress Classification for Tubesheet of Heat Exchanger With Semi-Ellipsoidal Heads

2013 ◽  
Author(s):  
Naoki Yoshimura ◽  
Shunji Kataoka ◽  
Takuya Sato
Keyword(s):  
Heat Exchanger ◽  
Exchange Process ◽  
Design Procedure ◽  
Analysis Model ◽  
Design Standards ◽  
Conventional Design ◽  
Economical Design ◽  
Stress Classification ◽  
Side Pressure ◽  
Heat Exchange Process

A fixed tubesheet type heat exchanger with semi-ellipsoidal heads which is dealt with in this paper has been adopted for refrigerant heat exchange process in LNG Plant. Since the conventional design standards, e.g. ASME Sec VIII Div.1 and TEMA, are not meant to be used for such a special type of heat exchanger, FEA should be performed to determine minimum required thickness of the tubesheet. The elastic design procedure uses a stress classification methodology to guard against failure due to gross plastic deformation. According to the design standards, mechanical stresses in the tubesheet due to tube-side and/or shell-side pressure are defined as the primary membrane and bending stress and are evaluated by comparing with allowable values of the primary stress. For the special type of heat exchanger, however, stresses in the tubesheet obtained by FEA are actually complex combination of primary and secondary stresses. Application of this conventional design approach to the FEA-calculated stresses in tubesheet may lead to over-conservative design. In helping to establish reliable and economical design of the tubesheet for such a special type of heat exchanger, authors conducted FEA investigation employing axisymmetric analysis model. Considering the geometric parameters, such as thickness of a tubesheet, heads type and shell dimension, the characteristics of tubesheet stresses was investigated and an appropriate stress classification was proposed.

scholarly journals Enhancement in Heat Exchange Process in a Shell and Tube Heat Exchanger using Nano-Particles

2020 ◽  
Vol 9 (3) ◽  
pp. 1791-1795
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Exchange Process ◽  
Flow Characteristics ◽  
Nano Particles ◽  
Tube Heat Exchanger ◽  
Nano Fluid ◽  
Heat Exchange Process ◽  
Shell And Tube ◽  
Improved Performance

Nanoparticles and nano-fluids are having its significant role in transforming and improvising the existing tools and techniques of science and other research. This experimental study deals with the parametric analysis of Al2O3 of size 20-30 nm and CuO of size 30-50 nm nanoparticles to improve the effectiveness of a shell and tube heat exchanger. Nanoparticles used in heat exchangers improved performance through better heat transfer characteristics. An experimental investigation was done on the forced convective heat transfer and flow characteristics of the nano-fluid flowing in a horizontal shell and tube heat exchanger under turbulent flow conditions. The heat transfer of nano-fluid is found higher than that of the base liquid at same mass flow rate and temperature difference. The heat transfer thus heat transfer parameters increases with an increase in volume concentration up to 1.6 % after which heat transfer decreases due to viscosity effects.

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.

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.

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