RUS

 

Drying-Thermal Processes Lab

>> Department of Mathematical Modelling


Head of the Laboratory

Shnip Aleksandr, PhD


History

Main Research Lines

Nucleation kinetics;
Heat and mass transfer in phase transitions and chemical conversions;
Heat and mass transfer in capillary-porous bodies;
Non-equilibrium thermodynamic theory;
Radiative and conductive heat transfer in orbital conditions; modeling of thermal regimes in space apparatuses;


Models and Theoretical Developments

Kinetic theory of mass transfer involving evaporation in porous bodies;
Non-equilibrium thermodynamic theory of relaxing systems;
Statistical theory of nucleation kinetics

Software
Program implementation of the mathematical model for thermal regimes of target apparatuses of the Belarusian spacecraft in orbital conditions and at ground thermal vacuum tests;
Bundled software for solution of special problems of the fire expertise “Heating”;
Software for visualization of biological cell magnetophoresis  

 


 

Main Research Directions
Theoretical and experimental studies of the processes of steady and unsteady of evaporative cooling, convective heat transfer, and structure features of laminar and turbulent vortex flows
Study of aerodynamics and hydrodynamics of vapor-air flow interaction with film and drop flows
Investigation of infrasonic noise propagation, moisture entrainment in the form of drops from a cooling tower and the influence of emissions of thermal and atomic power plants into the environment
As for applied use, these works are directed to enhance the processes of heat and mass transfer in industrial and power evaporative cooling equipment with the intent of augmenting its thermal performance.

Basic Developments

As a result of long-term experimental and theoretical studies, a set of engineering decisions on an essential enhancement of the cooling ability of chimney-type evaporative cooling towers of electric power plants is developed. The engineering developments are based on the aerodynamic methods for optimization of cooling air flow distributions at the entrance of a cooling tower and inside it.
All the below engineering developments are defended by BY patents.

Aerodynamic swirler.

It represents a system of slotted channels formed by vertical shields that are mounted in air entrance windows over the outer profile of the bottom of the cooling tower chimney and are directed so that the air flow moving in them would have one and the same tangential velocity component for each channel. Just this velocity determines the rotation intensity of a vapor-air medium inside a cooling tower. The aerodynamic swirler enables essentially improving the aerodynamics of air flows at the entrance of a cooling tower and inside it, enhancing heat and mass transfer processes, and thus augmenting the thermal efficiency of a cooling tower. In such a cooling tower, in addition to vertical and horizontal velocity components the resultant air flow velocity acquires one more component – tangential. This allows the cooling air flow to penetrate more deeply and uniformly in the radial direction, thus increasing the interaction path and the contact time of the incoming air flow with sprayed cooled water. This results in an additional (as compared to a cooling tower without an aerodynamic swirler) decrease in the reused water temperature in the cooling tower by several degrees, depending on the turbine operating conditions, climate and weather conditions. Note that in summer, the additional cooling of circulation water in the cooling tower by 1°C under other conditions being equal decreases the standard fuel consumption by 1.2 – 2.0 g per generation of each kilowatt-hour of electric power depending on the turbine type and initial vapor parameters.
The aerodynamic swirler was highly appreciated by specialists and recommended by the leading developer “BelNIIPIEnergoprom” and the concern “Belenergo” to be used in power engineering in the Republic of Belarus. It is also significant to note that cooling towers can be equipped with swirlers without stopping their operation and without large capital investment. Calculations and our experience in using aerodynamic swirlers show that such modernization is repaid during one-two seasons of operation and then makes a profit. For regions with warmer climate than in the Republic of Belarus, the cost efficiency of the swirler’s use is more essential.

Optimum control mechanism of winter horizontal jalousie facilities

The proposed new design of the jalousie facility augments the water cooling efficiency in the cooling tower due to the increase in the total flowrate of cooled air through the air entrance windows. This design permits the shields to be mounted at an assigned angle to the horizon and can be used independently or in combination with a version of an aerodynamic swirler. A combined use of the aerodynamic swirler and the proposed jalousie facility design enhances the cooling efficiency of the reused water in the cooling tower due to the improvement of the aerodynamics of the incoming air flow in the upper part of the air entrance windows.

Ventilation window with an air regulator

It is well known that the irrigation space of a continuous-flow cooling tower is characterized by a whole series of two-dimensional effects, showing that a considerable central zone of the sprinkler area is at a less density of air flowrate than the peripheral (more far from the center) zone of the sprinkler. Estimates and experiments are indicative of the fact that the size of the dead central zone can be 36 % and more of the total sprinkler area, which corresponds to the area of the circle 0.6 Rirr in radius where Rirr is the maximum radius of the sprinkler. Air enters such a dead zone via secondary flows and turbulent diffusion. This results in considerable water undercooling in the central part of the cooling tower.
The staff of the Laboratory proposed a cooling tower, where in the central part of the sprinkler a ventilation window is made. For the first time, this engineering decision was used in reconstructing cooling tower No 1 of the Grodno TEP-2 with an irrigation area of 900 m2.
A further development of this engineering decision was the patented idea of equipping a ventilation window with a special regulator of air flowrate through this window.

Air forced-supply module

The staff of the Laboratory proposed and patented a method of cooling the liquid in the chimney-type cooling tower, comprising a combined supply of cooling air into the cooling tower due to natural and forced thrust. Its difference from the known methods is that the forced thrust of cooling air is initiated only in the central zone of the cooling tower, while in addition to the natural thrust, in the peripheral zone the secondary flow of cooling air is created by ejecting its jets of the exhaust air flow of the central zone of the cooling tower.
To implement this method inside the stack at the irrigation system center of the cooling tower, the design of the air forced-supply module was proposed in the form of the internal mechanical-draft cooling tower equipped with a nozzle and an ejector at its exit. The above-mentioned mechanical-draft cooling tower is an active control element of the cooling ability of the feedback chimney-type evaporative tower where natural thrust and additional forced thrust inside the tower harmonize. As a result, the total combined effect exceeds essentially the sum of the effects of each component taken separately..

These developments can find wide use in power engineering, industry, and agriculture. In power engineering, they allow decreasing the specific fuel consumption for generation of electric energy, increasing the available power of power-generating units, and improving the operation of auxiliary processing equipment. Finally, their use in industry and agriculture permits decreasing specific energy and resource inputs for manufactured products.
The developments of the Laboratory are implemented in different-type aerodynamic swirler designs for cooling towers of electric power plants that generate their considerable economic efficiency.

Cooling towers No 1 and No 4 of the Minsk TEP-4 with the irrigation area of 3200 m2, equipped with different-version aerodynamic swirlers

Cooling tower No 1 of the Grodno TEP-2 with the irrigation area of 900 m2 with a built-in aerodynamic swirler and a ventilation window at the sprinkler center

The use of the aerodynamic swirler eliminates a gap between the installed and available capacity of thermoelectric power plants during the most intensive thermal period of their operation.
Shield-provided aerodynamic swirler of the chimney-type evaporative cooling tower No 2 of the Minsk TEP-3 (August 2008). Visualization of air flows in the upper part of the shields of the aerodynamic swirler of the chimney-type evaporative cooling tower No 4 of the Minsk TEP-4 (August 2007)

In 2009, the aerodynamic swirler was installed in the cooling tower No 6 with the irrigation area of 5100 m2 and the height of 110 m at the thermoelectric power plant in the city of Tianjin (Chinese People’s Republic). The tests supported the high operation efficiency of the aerodynamic swirler.

Appearance of the bottom of the cooling tower No 6 of the thermoelectric power plant in the city of Tianjin, equipped with a remote shield-provided aerodynamic swirler, designed by the co-workers of the Laboratory of Thermohydrodynamics (Chinese People’s Republic, August 2009)

At the Laboratory, the following test benches have been developed, manufactured, and found successful use:
-bench for investigating thermal processes and aerodynamics of chimney-type evaporative cooling towers of thermoelectric power plants;
-bench for complex investigation of unsteady hydraulic processes in water-distributing systems of towers;
-bench for working through the engineering decisions on the improvement of aerodynamics of incoming air flows for the main types of chimney cooling towers used in power engineering and industry.
The benches are supplied with required equipment and facilities. There is an automated system of information acquisition and handling in real time from the laboratory model of the chimney cooling tower via the wireline to the remote electronic computer. There is a set of equipment for optical visualization and analysis of the flow structure in optically transparent media; the bench is equipped with a two-channel imitator of wind loads on the test models of cooling towers, etc.


RUSed developments

Bobruisk TEP-2, cooling tower (1)

Gomel TEP-2, cooling towers (2)

Tbilisi State Electric Power Plant “Mtkvari Energy” (Georgia)

Appearance of the bottom of the cooling tower No 6 of the thermoelectric power plant in the city of Tianjin, equipped with a remote shield-provided aerodynamic swirler, designed by the co-workers of the Laboratory of Thermohydrodynamics (Chinese People’s Republic, August 2009)

Cooling towers of the Minsk TEP-4, TEP-3 (4, 2)

Cooling tower of the Grodno TEP-2 (1)


Equipment

Bench for studying thermal processes and aerodynamics of chimney evaporative cooling towers of thermoelectric power plants

Bench for complex investigation of unsteady hydraulic processes in water-distributing systems of cooling towers

Bench for working through the engineering decisions on the improvement of aerodynamics of incoming air flows for the main types of chimney cooling towers used in power engineering and industry


 

 

 

 

 
    Национальный правовой Интернет-портал Республики Беларусь             

2010 © Heat and Mass Transfer Institute, National Academy of Sciences of Republic of Belarus

15, P. Brovka Street, Minsk, 220072
Reception-room: +375(17)2842136, fax: +375(17)2922513
E-mail: office@hmti.ac.by