V. L. Nizovskii

Atomization of superheated water: Results from experimental studies

Results from experimental studies of characteristics of atomization of water superheated relative to saturation temperature are presented. The data on disperse composition of a droplet flow are obtained depending on the temperature of water superheat. It is shown that, at a water temperature of 200–240°C, the distribution of droplets as to their size appears to be bimodal, with about 70% of droplets (by mass) having a diameter of not more than 5–6 μm.

Experimentally studying TV3-117 gas-turbine unit characteristics at superheated water injection into a compressor

The results from experimentally studying TV3-117 gas-turbine unit (GTU) characteristics at injection of cold and superheated (metastable) water to the inlet of the GTU compressor are presented. In the latter case, the finer water atomization is obtained. The water injection makes it possible to considerably increase the unit power. At a constant temperature of the working fluid downstream of the turbine combustion chamber, water injection in an amount of 1% of the air flow rate provides an increase in the turbine power by approximately 12% and expands GTU controlling potentialities. The use of the metastable superheated water atomization enables one to more reliably implement the technology of water injection into a compressor, especially into intermediate compressor stages. However, it requires accounting for operational conditions of particular installation. Due to small water droplet residence time in the compressor flow path, even with fine water atomization, in aircraft engine derivative power turbines, about 15–20% of moisture injected have no time to completely evaporate within the compressor. When injecting cold water, this figure is from 5 to 10% larger.

Special features of the behavior of the liquid phase in high-speed compressors of aircraft engine-derivative gas-turbine units and their impact on characteristics and effectiveness of “wet” compression

The paper deals with the processes of “wet” compression with injection of water into axial-flow compressors of aircraft engine-derivative gas-turbine units, which are characterized by a relatively high speed of rotation and small standard dimensions. Given for two typical machines are the results of analysis of the behavior of water films on the surfaces of stator and rotor blades at different compressor stages (including the separation of moisture to the casing) and their impact on the characteristics and effectiveness of the process of “wet” compression.

Microbubble boiling: Mechanism of the process, objectives and methods of investigations

Results are given of analysis of experimental studies devoted to the mechanism of subcooled liquid boiling under conditions of forced flow and, in particular, to its extreme case realized under high heat fluxes, i.e., microbubble boiling. The problems are formulated which are associated with experimental investigation of structural characteristics and dynamics of microbubble boiling. The description is given of the experimental stand and diagnostic system for solving the problems set.

On the nature of bimodal drop distribution over sizes under superheated water atomization

A description of the possible succession of the processes resulting in bimodal drop distribution over sizes under superheated water atomization is presented. The first one consists in fragmentation of the liquid discharging from the atomizer and formation of 5- to 15-μm liquid fragments due to the baro-capillary effect; the second one results in fragmentation of a part of these fragments under the action of the rapidly expanding vapor bubbles (flashing).

Evolution of a superheated water spray in air flow

Experimental data on the distribution of dispersion parameters, shape of superheated water spray, and its evolution in a carrying air flow are presented. It is shown that the layout of spray system atomizers must be developed taking into account the fact that the spray of finely dispersed droplets is prone to intensive stringing.

Power increasing reserves in gas-turbine unit-based independent power units

The possibilities of broadening the control range of the gas-turbine power unit by water injection into various points of the flow path of its compressors including compressed air are analyzed. The results from experimental investigations of a turbine of 1.2 MW capacity are presented.

Atomization of superheated water: Practice of investigation of complicated disperse systems

The design and layout of a system for measurement of the dispersion composition of an air-droplet mixture on the basis of monochromatic emission scattering are described. The pattern of processing the scattered emission indicators is presented, and the results of measurements of the dispersion composition of the air-droplet mixtures are given.

Superheated Water Atomization: A Possibility of Obtaining Sprays of Droplets of Micron Diameters

In the given brief communication, new experimental data on superheated water atomization are presented. It is shown that in contrast to the case of short cylindrical nozzles, which provide bimodal water–droplet sprays, the application of divergent nozzles makes it possible to obtain one-modal water atomization with droplets of about micrometer diameter. This is explained by the changes in the mechanism of superheated water jet fragmentation.