Effects of Al2O3 nanoparticles on the formation of inorganic scale on heat exchange surface with and without scale inhibitor

2019 ◽  
Vol 151 ◽  
pp. 1-10 ◽  
Author(s):  
Le-Tian Wang ◽  
Hong-Hua Ge ◽  
Yu-Tian Han ◽  
Chuan Wan ◽  
Jun-Yi Sha ◽  
...  
Keyword(s):  
Heat Exchange ◽  
Al2o3 Nanoparticles ◽  
Scale Inhibitor ◽  
Heat Exchange Surface ◽  
Exchange Surface

Temperature control in a chemical reactor through variable area of the heat transfer surface. Simulation analysis

1982 ◽  
Vol 47 (2) ◽  
pp. 430-445
Author(s):  
Josef Horák ◽  
Zina Valášková
Keyword(s):  
Heat Exchange ◽  
Simulation Analysis ◽  
Batch Reactor ◽  
Chemical Reactor ◽  
Rate Of Change ◽  
Action Variable ◽  
Heat Exchange Surface ◽  
Relay With Hysteresis ◽  
Exchange Surface

An algorithm has been developed and on a mathematical model analyzed to stabilize the reaction temperature of a batch reactor. The reaction has been a zero-order one and the reactor has been operated in a instable operating point. The action variable is the heat exchange surface whose area is increased if the temperature is above, or decreased if the temperature is below the set point. The following two-point regulators have been studied: An ideal relay, a relay with hysteresis and an asymmetric PD relay. The effect has been discussed of the parameters of the regulators on the quality of regulation. Stability analysis has been made of the stationary switching cycles and the domains of applicability have been determined for individual regulators with respect to the rate of change of the area of heat exchange surface.

Thermodynamic Estimate of Minimal Dissipation for Heat Exchange System

2008 ◽  
Author(s):  
Andrei A. Akhremenkov ◽  
Anatoliy M. Tsirlin ◽  
Vladimir Kazakov
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Load ◽  
Point Of View ◽  
Exchange System ◽  
Heat Exchange System ◽  
Heat Exchange Surface ◽  
Minimal Dissipation ◽  
The Difference ◽  
Exchange Surface

In this paper we consider heat exchange system from point of view of Finite-time thermodynamics. At first time the novel estimate of the minimal entropy production in a general-type heat exchange system with given heat load and fixed heat exchange surface is derived. The corresponding optimal distribution of heat exchange surface and optimal contact temperatures are also obtained. It is proven that if a heat flow is proportional to the difference of contacting flows’ temperatures then dissipation in a multi-flow heat exchanger is minimal only if the ratio of contact temperatures of any two flows at any point inside heat exchanger is the same and the temperatures of all heating flows leaving exchanger are also the same. Our result based on those assumptions: 1. heat transfer law is linear (17); 2. summary exchange surface is given; 3. heat load is given; 4. input tempretures for all flows are given; 5. water equivalents for all flows are given.

Computer simulation of the reliability of the heat exchange surface of the steam turbine condenser

2022 ◽  
pp. 1748006X2110672
Author(s):  
Krzysztof Bernard Łukaszewski
Keyword(s):  
Heat Exchange ◽  
Steam Turbine ◽  
Cooling Water ◽  
Operating Conditions ◽  
Time Varying ◽  
Turbine Condenser ◽  
Heat Exchange Surface ◽  
Steam Turbine Condenser ◽  
The Relationship ◽  
Exchange Surface

The aim of the article is to demonstrate the relationship between the adaptive regulation of the heat exchange surface to specific operating conditions of a steam turbine condenser and the reliability and availability of this surface in a specific period of time. The article exemplifies the relationship between the settings of the condenser heat exchange surface and the resulting changes in the reliability structures of this surface. The method of creating a mathematical model of reliability estimation, which is characterized by the variability of the reliability structures of the heat exchange surface in relation to specific operating conditions in a specific period of time, was indicated. Then, exemplary simulations of the adaptation of reliability structures of specific pipe systems constituting the condenser’s heat exchange surface to specific processes of operation of this condenser are presented. The simulations refer to the time-varying thermal loads of the condenser, the time-varying mean thickness of the sediments, and changes in the temperature of the cooling water at the point of its intake over time. The adaptation of certain reliability structures consists in the adaptation of specific systems of pipes through which the cooling water flows to the currently existing operating conditions of the condenser in order to maintain the desired reliability of the heat exchange surface for a specified time. This is done by enabling or disabling the flow of cooling water through a given number of pipes in specific systems under given operating conditions. On the basis of computer simulations, the reliability functions, and the availability functions of the subsystem under consideration were estimated.

scholarly journals About mathematical modeling of aerodynamic characteristics in devices with a leakage of the impact systems of plane-parallel streams on the heat exchange surface

2018 ◽  
Vol 170 ◽  
pp. 03024
Author(s):  
Larisa Haritonova ◽  
Valery Azarov ◽  
Igor Stefanenko
Keyword(s):  
Heat Exchange ◽  
Heat Exchangers ◽  
Aerodynamic Resistance ◽  
Aerodynamic Characteristics ◽  
Plane Parallel ◽  
Heat Exchange Surface ◽  
Parallel Streams ◽  
The Impact ◽  
The Mathematical Model ◽  
Exchange Surface

The article is devoted to the development of the general aerodynamic theory in case of a leakage by the systems of plane-parallel impact jets on the plane heat exchange surface [1-2]. An analytical generalization of data on aerodynamic resistance with the blowout of flat surface by the system of the plane-parallel impact jets was implemented. These data were obtained as a result of the application of mathematical theory of planning an experiment. The equations of regression are the mathematical model of process. Functional dependences between the constructive factors and the regime parameters of these first obtained experimental dependences on aerodynamic resistance in the jet heat exchangers with the leakage of air in the form of the system of plane-parallel jets were established. Results of work can be used in developing of different methods of calculation for various new designs of highly effective heat exchangers or their optimization for various branches.

Determining the heat-exchange surface of an annular compressor condenser

1972 ◽  
Vol 8 (10) ◽  
pp. 903-904
Author(s):  
V. I. Ushakov ◽  
B. N. Sopin ◽  
A. A. Glushakov
Keyword(s):  
Heat Exchange ◽  
Heat Exchange Surface ◽  
Exchange Surface

Mathematical Models of the Ocurved Spring Tubes Surfaces

2019 ◽  
Vol 16 (11) ◽  
pp. 4554-4559 ◽  
Author(s):  
Valeriya Leonidovna Vorontsova ◽  
Alfiya Gizzetdinovna Bagoutdinova ◽  
Almaz Fernandovich Gilemzianov
Keyword(s):  
Heat Exchange ◽  
Mathematical Models ◽  
Heat Exchangers ◽  
Coil Spring ◽  
Compact Heat Exchangers ◽  
Curved Channels ◽  
Exchange Processes ◽  
Heat Exchange Surface ◽  
The Creation ◽  
Exchange Surface

One of the ways to intensify heat exchange processes is the creation of compact heat exchangers with a developed heat exchange surface. It is known that coil-type channels provide a developed heat exchange surface and belong to one of the most efficient and technological designs of heat exchange elements. In this regard, the authors proposed a small-size heat exchanger of the “pipe in pipe” type with an internal coil spring-twisted channel, and the authors of the proposed article developed mathematical models describing the heat-exchange surfaces of pipes of complex configurations, including coil spring-coiled channels. The equations of heat transfer surfaces are written in vector-parametric form based on the fundamental principles of analytical and differential geometry. In order to verify the adequacy and visualization of the written equations, surfaces were constructed using the Matlab application software package. The proposed mathematical models can be used in computer simulation of hydrodynamic processes during the flow of liquid media in curved channels, which will allow to explore and further optimize their internal geometry by changing the parameters of the equations. This work is a continuation of research on the creation of efficient heat exchangers.

scholarly journals Efficiency of different types gas heaters for chimney anticorrosion protection systems of boiler plants

2020 ◽  
pp. 5-16
Author(s):  
N. Fialko ◽  
◽  
A. Stepanova ◽  
R. Navrodska ◽  
S. Shevchuk ◽  
...  
Keyword(s):  
Heat Exchange ◽  
Geometric Parameters ◽  
Planning Theory ◽  
Water Heating ◽  
Anticorrosion Protection ◽  
Gas Heating ◽  
Heat Exchange Surface ◽  
Different Types ◽  
Exchange Surface ◽  
Plate Type

The of researches results of exergy efficiency and optimization of parameters of different types gas heaters by used for anticorrosion protection of gas exhaust ducts of heating boiler plants equipped with exhaust gas heat recovery systems are presented. The choice of a complex technique for analyzing the efficiency of gas heaters, which makes it possible to obtain functional dependences of the selected efficiency criteria on the geometric parameters of the heat exchange surface of gas heaters for solving optimization problems is substantiated. Such a technique can be a technique based on exergy methods and statistical methods of experiment planning theory. This technique by an insignificant number of initial parameters required for calculation, and by the simplicity of calculation and analytical methods for obtaining exergy characteristics is characterized. The work considered three types of gas heaters: water-heating (water-gas) and two gas-heating (gas-gas) pipe and plate type. The heat exchange surface of the water-heating gas heater is assembled from transverse-finned bimetallic (steel base and aluminum fins) pipes, gas-heating pipe-type - from steel pipes with circular turbulators flow, and gas-heating plate-type - from smooth steel plates. The general system of balance equations used in this complex technique, and also its the basic stages, are presented. It is noted that the choice of complex criteria for assessing the efficiency of gas heaters is carried out according to the degree of sensitivity of the criteria to changes in the operating and geometric parameters of gas heaters. Using the proposed sensitivity coefficient, the degree of sensitivity of different efficiency criteria has been analyzed and it has been established that one of the most sensitive to changes in the geometric parameters of the heat exchange surface of gas heaters is the heat-exergy criterion. The results of the corresponding calculations for each of the three gas heaters are presented. It has been established the most exergetically effective is a water-heating gas heater, followed by gas-heating gas heaters, of plate and tube types respectively.

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