Forecasting of the efficiency indicators of the use of boiler and furnace fuel in the non-traction power engineering of railway transport based on the model of temporaryth row

The article considers the solution of the problem of constructing forecast values for a long period of changes in the value of the specific consumption of boiler and furnace fuel by boilers for a geographically distributed company-Russian Railways, taking into account the use of various types for the main types of fuel used in the generation of thermal energy: natural gas, heating oil, coal and brown coal. A mathematical model based on time series using the Bollinger method is proposed, which includes elements of extrapolation and modeling. An example of calculating the change in the values of specific consumption in the future until 2035 in the whole railway network is given. A simulation of the change in this value is performed for the variant fractions of substitution of one type of fuel with another. The possibility of determining long-term forecast indicators using a time series model is shown.

Analysis of Efficiency upon Enhancing the Fuel Combustion Completeness in the GTU Burners Using Fuel Gas Heating up

One main characteristic of the gas turbine unit (GTU) burner is its fuel combustion completeness, which affects directly the efficiency of the power plant along with CO and unburnt hydrocarbons CnHm emissions. The aim of this work was the research on the application of the fuel heating-up as an alternative method for increasing the fuel combustion completeness and controlling the emission of harmful agents. This goal is achieved by obtaining experimental data on the emissions of CO and NOx at different temperatures of the fuel gas supply to the combustion chamber. The most significant result of the work is the experimentally confirmed possibility of increasing the combustion efficiency (decreasing CO) by heating the fuel gas while maintaining constant gas-dynamic characteristics of the chamber. The significance of the results obtained consists in the experimental confirmation of the combustion quality control only by heating the fuel gas without changing the operating and design characteristics of the combustion chamber. The fuel combustion low completeness can cause the burner unstable operation in the form of the unsteady pre-blowout burning combined with the pressure oscillations in the burner. At present, methods for ensuring the increase in stability and completeness of the fuel combustion are related to the air rate and temperature changes at the inlet. However, the use of these methods can be unwanted because of their causing the decrease in the coefficient of efficiency and in the resource of the ‘hot part’ of the gas-turbine facility.

Heating of natural gas before expander - generator unit

The article discusses the replacement of throttling at the stations of technological lowering of the pressure of main natural gas by an expander-generator technology that allows the production of a cheap one with high environmental indicators. The disadvantage of this method of generating electricity is a significant cooling of the gas at the outlet of the expander, which necessitates its heating. The efficiency of the expander-generator set is largely determined by the adopted gas heating scheme. Achieving such heating temperatures is possible only by using high-potential energy resources, which are present in the technological equipment of gas distribution stations in the form of gas heaters with an intermediate heat carrier, designed to heat gas before expansion. Calculations of the amount of fuel gas required for heating the main natural gas in front of the expander-generator unit at the gas distribution stations under consideration have been carried out. The results of the study of the influence of the temperature of gas heating in front of the expander on the consumption of fuel gas supplied for heating and the numbers of heaters are presented. An analytical dependence of the electric power of the heat pump installation on the difference between the total power consumption of the compressor and the power of the air turbine is obtained.

Influence of the position and energy of local rapid heating of the supersonic gas flow on the position of the separation point on the surface of airfoil

Using numerical simulation, the study of the process of rapid local energy release in supersonic flow in a two-dimensional unsteady case and the process of separation point shift by a gas-dynamic perturbation caused by the energy input into the flow were carried out. The flow around the airfoil was modeled as laminar, and local heat release as a instantaneous isochoric process without changing the gas density. The value of energy input and the place of gas heating on the surface of the airfoil were varied. The cases of initiation of energy input at a certain distance before and after the initial position of the separation point, as well as immediately before the separation point, were considered. During obtained flow patterns processing, the displacement of the separation point position downstream, the time of this displacement, the position and size of the separation region with reattachment and the lifetime of this flow zone were determined. The obtained data can help to choose a strategy for initiating energy input in a repetitively pulsed regime, as well as in a regime of a variable position of energy release on the surface of a body, streamlined by compressible gas flow.