V. I. Zalkind

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.

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).

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.

Conjugated heat and electrophysical characteristics of K-phase films on electrode walls of the channel of an aluminum-hydrogen MHD generator at high thermal and electric parameters

The utilization of aluminum as an intermediate energy carrier with subsequent production of high-temperature hydrogen in reactions of hydrothermal oxidation makes it possible to build high-performance thermal-power cycles with an MHD generator, with a real prospect for their utilization in emergency and high-peak power plants [1]. One of the main problems of efficient operation of an MHD generator channel is the deposition of K-phase in the form of conducting melt films of Al2O3 on the fire surface of MHDG channel walls. As this takes place, there are leakage currents through the melt films in the induced transversal and Hall fields, which are accompanied by Joule heat-evolution. The peculiarities of formation, flow, and thermal regime of such a film on the fire walls of MHDGs in the induced Hall and transversal fields were studied in this connection, as well as the peculiarities of current flow with regard to temperature dependencies of the conduction and the viscosity of the Al2O3 melt. The results of investigation make it possible to estimate the influence of such films on aluminum-hydrogen MHDG performance.

Superheated Water Atomization: Some New Aspects of Control and Determining Disperse Characteristics of Atomization Plume in Micron and Submicron Ranges of Droplet Size*

New experimental data on superheated water atomization is 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 micron diameter being obtained. This fact is due to changes in the mechanism of superheated water jet fragmentation and it is very important for engineering applications. A modified experimental technique for processing integral monochromatic scattering indicatrix was developed and tested. In addition, a new calculation code was worked out for calculating atomized water drop-size distribution (on the basis of Mi theory) in micron and submicron ranges.

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.

Special features of heat transfer under conditions of heat protection of high-temperature firing walls of components of modern power-generating units by way of tangential injection

In order to more precisely define the characteristics of heat transfer under conditions of protection of firing wall by means of tangential injection in the case of its high temperature (in particular, higher-thanadiabatic temperature) and to assess the effect of degree of turbulence of the incoming gas flow on heat transfer, a numerical investigation is performed under conditions of parameters typical of combustors of gas-turbine plants (GTP) with high parameters of the working medium. In so doing, the heat flux distribution, the profiles of turbulence intensity, the distribution of turbulent viscosity in the injection zone region under study, and other characteristics are determined. The low-Reynolds k-ε model with wall functions and a new model of turbulent viscosity without wall functions are employed. It is found that a maximum of turbulent viscosity takes place behind the exit section of the injection slit with a shift to the main flow under conditions of tangential injection on an isothermal surface with a temperature much in excess of injection temperature (in a more general case, Tw > Tad). This causes impairment of heat protection by injection, i.e., an increase in heat fluxes in the computational domain compared to heat fluxes calculated using integral methods.