Investigation of the swirled flow structure in the improved four-vortex furnace model

The flow structure in a model of promising four-vortex furnace is investigated using three-dimensional laser Doppler anemometry method (3D-LDA). Using the “minimum total pressure” criterion, a vortex flow structure was visualized: the core looks like a deformed elliptical cylinder. Results has been compared with early PIV experiments and showed good agreement. The mathematical model for full-scale furnace numerical studies can be verified using these data.

Calculation analysis of heat transfer in a four-vortex furnace of a pulverized coal boiler when operating at various loads

The work is devoted to the mathematical modeling of heat and mass transfer processes during flare combustion of coal dust in a four-vortex combustion chamber. For modeling, a set of interrelated models is used that describes the gas movement, thermal and radiant energy transfer, the processes of destruction and burnout of coal particles, and the formation of NOx. The simulation results showed that in a wide range of changes in the boiler load in the furnace, a stable four-vortex flow structure is formed with a fairly uniform temperature distribution in the furnace volume and a low level of NOx formation.

Investigation of the direct-flow jets vortex motion in the M-shaped boiler invert furnace

For advanced ultra-supercritical parameters (A-USC) of steam, the design of an M-shaped boiler is proposed, designed to operate in a 500 MW unit on a lean coal (grade TR). The boiler profile is selected from the condition of minimizing the length of the main steamlines made of expensive nickel-alloy steel. With regard to this boiler, a scheme has been developed for pulverized coal combustion in an invert furnace using direct-flow burners and nozzles. Research has been carried out on the physical model of the furnace in the implementation of this combustion scheme: a qualitative study of the trajectories of the burner jets, jets of secondary and tertiary air obtained by their hot spark visualization; quantitative determination of the main characteristics of burner jets and their weight gain. The studies have shown the high efficiency of the recommended scheme of the furnace-burner device: a staged supply of the oxidizer along the flame length and along the furnace height is organized; the dynamic pressure of jets on the furnace wall tubes is excluded; vortex furnace aerodynamics should provide a high degree of burnout of coal dust particles; air jets evenly fill the horizontal section of the furnace; the ejection capacity of turbulent jets is much higher than for a flat submerged jet.

Aerodynamic Characteristics of the Combustion Process of Sawdust in a Vortex Furnace with Counter-Swirling Flows

The aim of this work is to study the working processes of burning the low-quality fuels, namely, the saw dust in the swirling-type furnaces with an opposite twisted motion of the air. The goal was achieved using the physical and mathematical modeling of the flows interaction. The article presented the results of numerical study of aerodynamic characteristics of burning the saw dust in the swirling-type furnace with the opposite twisted air flows. For the research, the facility was used for the saw dust burning with the air supply into the lower and upper zones of burning. The most essential result of the work was modeling of the working process at the ratio of the flows of the primary air and secondary air without the fuel admixture, equal to 0.2. The tangential rate of the flow changed according to the horizontal sections from 3-5 m/s to 40-42 m/s and with respect to the furnace height from 51 m/s to 30 m/s. The average angular rate of the mixture changed relatively the furnace height in the ranges of 171-500 l/s to 100—300 l/s. The significance of the results obtained consists in determination of the possibility of increasing the efficiency of the work of the furnace facilities at the expense of the introduction of the primary and secondary air flows. In this situation, the optimal ratio of consumptions of primary and secondary air was 0.2. Thus, in this work the consumption of primary air was 1.285 kg/s, the consumption of the secondary air was 0.255 kg/s.

3D-LDA diagnostics of a swirled flow in the model of an improved four-vortex furnace

The three-component Laser Doppler Anemometry method (3D-LDA) was used to study the internal aerodynamics of an experimental model of a promising furnace with a four-vortex scheme for burning coal fuel. Distributions of the averaged velocity and velocity fluctuations are obtained. There are no the pronounced peaks in the spectrum of velocity fluctuations, so we can speak about the stability of the investigated flow. The studied model is characterized by a high level of velocity fluctuations, provided for effective mixing of the pulverized coal mixture in the combustion chamber of the furnace.

Experimental Study of Temperature Distribution in a Cyclone-Vortex Furnace

This article describes the experience and results of experimental study of the temperature distribution in the refractory lining of the gas and liquid fuel cyclone-vortex furnace (CVF). Temperatures were measured with type K thermocouples. Most of the thermocouples are located a depth of 25 mm from the surface combustion chamber. With increasing boiler load observed decrease in temperature and increase of plating unevenness of the temperature distribution in the combustion chamber. This is due to the redistribution of heat generated between the combustion chamber and the firebox as the load increases. The results of heat transfer studies in CVF will lead to a reduction in the thickness of the lining, modernization of the CVF structure. In the future, abandon the use of refractory lining in CVF

Three-component diagnostics of swirling flow in the model of an improved four-vortex furnace

The spatial structure of a swirling turbulent flow has been investigated based on the three-component laser Doppler anemometry method in an isothermal laboratory model of a four-vortex furnace. The structure of the vortex cores of the flow with the shape of a deformed vertical elliptical cylinder is visualized using the ?minimum total pressure? criterion. The spectrum of velocity pulsations indicates the absence of unsteady periodic vortex structures, which means the occurrence of a stable vortex flow in the volume of the combustion chamber.