Analysis and Simulation of the Motion of Particles near the Heat Exchange Surface Immersed in a Fluidized Bed

2021 ◽  
Vol 55 (1) ◽  
pp. 41-52
Author(s):  
O. Yu. Milovanov ◽  
R. L. Is’emin ◽  
D. V. Klimov ◽  
V. S. Kokh-Tatarenko ◽  
O. M. Larina
Keyword(s):  
Heat Exchange ◽  
Fluidized Bed ◽  
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.

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