Development of Auto­oscillating System of Vibration Frequency Sensors with Mechanical Resonator

At present, resonator sensors with an auto-oscillating system have a number of advantages in comparison with the known sensors with frequency output. In this case, developed auto-oscillating systems of resonator sensors are very specific; their elements are oriented toward a particular type of resonator and possess a certain degree of nonlinearity, which makes studying and modeling such systems impossible.In the present work, analytical expressions were obtained for the reduction of parameters of mechanical systems of resonators to the lumped ones. This allowed us to apply the methods of research into nonlinear systems of control to the analysis of AOS and to receive the expression of transfer function of nonlinear resonator with consideration to the nonisochronicity. A structure of auto-oscillating system with a nonlinear resonator is devised, which was not explored earlier.With the purpose of selecting the character of nonlinearity in the elements of feedback and mechanical resonator of the assigned type in AOS to warrant the assigned stability of frequency and amplitude of auto-oscillations, we performed imitation simulation in the Matlab Simulink programming environment. The simulation demonstrated that a nonlinear amplifier at work with a nonlinear mechanical resonator provide for the auto-oscillating system that is stable by frequency and amplitude. Thus, auto-oscillating system of the devised structure can be used in the design of vibration frequency sensors

Examining the Kalman Filter in the Field of Noise and Interference with the Non-Gaussian Distribution

We have developed a sequential recursive Kalman Filter algorithm to filter data in the field of the non-Gaussian noise distribution to be used in measurement instruments. A special feature of the constructed Kalman Filter algorithm to filter data with the non-Gaussian noises is the absence of a need to determine a priori the statistical characteristics of noise.The applicability of the developed Kalman filtering procedure was tested by processing different distribution laws: the Cauchy, Pareto noises, normal and logistic distributions. The effectiveness of the devised filtering procedure is confirmed by applying the filter when processing experimental data with different laws of noise distribution. We have conducted approbation of the developed procedure for the Kalman filtering based on data obtained experimentally, with respect to the superposition of noise distribution laws. The a priori estimate for a filtering error when the number of iterations exceeds 30 tends to zero.The devised filtering procedure employing the Kalman filter could be used when performing the metrological certification of measuring instruments under industrial conditions. Under such circumstances, measuring information could become noisy due to various noises, including those that are not governed by the Gaussian distribution law. The filter could be used when processing data from control systems over state parameters, implemented on the principle of a magnitude threshold control.The applied aspect of the scientific result obtained implies the possibility of extending the scope of application of the classic Kalman filter in measurement instruments. This is a prerequisite for the development of a generic filtering algorithm using the Kalman filter

Examining a Cavitation Heat Generator and the Control Method Over the Efficiency of Its Operation

The cavitation heat generator for decentralized heating of industrial buildings and facilities was examined and implemented for actual operation. On this basis, a thermal system for decentralized heating of buildings was designed and studied. The circuit of the thermal system differs by the following feature: two connected cavitation heat generators are connected in series for heating of the liquid. At the same time, the heated liquid passes through a heat generator operating at high frequency, then through a heat generator operating at lower frequency. In the generator with high frequency, smaller cavitation embryos are excited, which increase in size in the generator with low frequency. This leads to increased impulses of cavitation pressure and increases the effect of cavitation.On this basis, a heat system for decentralized heating of buildings was designed, and studied, with its energy efficiency. To increase energy efficiency of the thermal system with cavitation heat generators, their sequential installation was proposed. The heated liquid must pass successively through a heat generator operating at high frequency, then through a heat generator operating at lower frequency.The efficiency of the system developed exceeds 18 % compared to the system of centralized heating by natural gas, which is a convincing prospect of use.A method for effective control over the cavitation process during operation of a heat generator was developed, based on the suppression of waves of oscillatory energy of the object. The method is based on direct measurements of vibrations – a parameter characterizing the process of cavitation. Approbation of the method for control over effectiveness of the cavitation process was carried out by measuring the vibrations at various temperatures of liquid at the outlet

Application of Electromagnetic Fields for Intensification of Heat and Mass Exchange in Combined Gas-liquid Processes

To date, thermal rectors with submersible combustion devices with efficiency of more than 100 % relative to the lowest heat of combustion are known. This method of heating is more universal and energy efficient due to the absence of heat losses in transportation and maximum utilization of the carrier heat. This opens up broad prospects for the use of these energotechnological facilities in residential gas heating systems.This work has studied the effect of electromagnetic fields having intensity gradient in the direction of motion of the contacting phases on the process of mass transfer between counter-current-moving gas and liquid phases. It was shown that the optimal method of intensification of heat and mass transfer in the submerged combustion devices is oscillation of the contacting phases under action of an electric spark discharge. Design solutions were proposed for intensifying the heat and mass transfer process and increasing the energy efficiency of operation of thermal reactors with the submersible combustion devices.To evaluate the effect of magnetic and electric fields upon their application, it was proposed to use the developed vibrofrequency measuring transducer with a cylindrical-type resonator. Application of such control method makes it possible to measure total frequency-modular oscillations of the contacting phases. In this case, there is no need to control characteristics of magnetic and electric fields and assess their individual effects on the intensity of oscillations in the contacting gas-liquid phases

Thermal Treatment of Concentrated Liquid Toxic Waste and Automatic Control of Process Efficiency

One of the promising approaches to reducing the energy consumption in the thermal distillation of liquid toxic waste is the use of immersion combustion units with the efficiency of more than 100 % relative to the lower calorific value. The development of the method of LTW thermal distillation (evaporation) in volume by means of immersion combustion units will allow wide application of the technology in the industry.The energy-efficient technological system based on deep thermal evaporation in the ICU is developed. It is shown that the developed EETS has improved characteristics in comparison with the existing thermal treatment systems. The proposed solutions allow simplifying the vat residue processing after the LTW treatment process.The final product of thermal distillation of toxic waste is a dry residue that does not require repeated or additional processing.As an efficiency indicator of the LTW distillation complex, it is proposed to use the density of evaporated effluents. The paper proposes to use the vibration method of density control with simultaneous measurement of density and viscosity of controlled LTW. The structure of the automatic density control scheme allows compensating for a decrease in the resonator quality factor due to the damping of its vibrations by a viscous mediu

Intensification of the Process of Metallizing Tungsten­containing Ore Raw Materials by the Powder Metallurgy Method

X-ray diffraction phase analysis of samples performed on a DRON-6 diffractometer has shown that the processes of CaWO4 transition to WC and W2C had the highest probability in the temperature range of 1,173–1,473 K. The end-product CaWO4, thermally treated with carbon, was represented by carbon in oxycarbide and carbide phases. The processes of tungsten reduction from its oxides through the phases of formation of tungsten carbide and oxygen compounds (higher and lower) and finally tungsten metal were shown. Basic chemical and phase transformations occurred within the temperature range of 300–1,800 K. This opens the prospect of producing tungsten as an alloying material without formation of liquid phases in a heterogeneous system and enables production of tungsten based alloying material at relatively low temperatures which significantly reduces power consumption. Qualitative and quantitative composition of charge materials for laboratory studies and industrial tests in a form of briquettes for metallization of tungsten-containing compounds in a furnace with induction heating was presented. The mechanism of phase and structural transformations occurring in reduction of tungsten from scheelite concentrates in the temperature range of 1,273–1,473 K and microanalysis of samples of chemical transformations were studied. A furnace unit with induction heating in which industrial tests were performed in stages was schematically shown.The tests have shown that a 1.3 times sample weight reduction and a 23 % specific density reduction occurred in the process of heat treatment of the samples based on scheelite concentrate.Several batches of spongy tungsten instead of standard ferrotungsten were produced and tested in smelting high speed steels. Advantages of the new technology of tungsten metallization from a scheelite concentrate and positive efficiency of using the new material in special metallurgy were shown

Research of the Impact of the Method of Heating of Heat Units on the Qualitative Characteristics of Treated Materials

An analytical method for calculating the chemical potentials of the components of the gas-solid system based on thermodynamic calculations of carbon potentials of the С–О–Н–N gas mixture (combustion products of the methane-air mixture) and the solid phase (alloyed steel) is developed. Dependences describing the influence of the main parameters of heating the medium composition, flow rate, as well as their interaction, on metal losses associated with decarburization are obtained.Thermodynamic calculations of carbon potentials of alloyed steel and natural gas combustion products of different composition (α=0.2÷1.2), metal and combustion products temperatures of 1,100÷1,500 K are performed.Based on the analysis of the structure of the thermal and diffusion boundary layers, it is proved that the decrease in the temperature of the layer of combustion product flowing around the solid product and surface flow rate reduces the diffusion flow of carbon in the boundary layer. This effect reduces the decarburization of steel.It is found that when heating the heat unit according to the principle of indirect radiant heating (IRH) during the operation of the flat-flame burner, the main gas volume, localized at the metal surface, has a temperature significantly lower than the layer adjacent to the lining. This reduces the metal loss with decarburization compared with furnaces of the traditional heating system.Combustion of gas in flat-flame burners with an intense circulation of combustion products in the working space of the heat unit ensures that the heated products have a uniform composition of combustion products corresponding to a practically equilibrium one. This allows recommending flat-flame burners for widespread use in modern heat-power units in the industr

Design and Study of the Energy­efficient Unified Apparatuses for Energy­technological Manufacturing

The improved industrial sample of the rotor-pulse heat generator (RPH), integrated into the thermal heating systems of industrial buildings, was produced. Rotor-pulse generators do not occupy significant positions in the market of heating equipment because of the lack of reliable data on effectiveness of the use of such equipment in the thermal heating systems of industrial facilities.The design of the developed cavitation chamber was changed, parameters of the channels, located between the rotor and the stator, were determined. It was found that the optimal width of the gap between the rotor and the stator channels at maximum efficiency of 0.7 was 8–10 mm. When integrating the cavitation chamber of the RPH into the thermal system, the design of the heat exchanger "pipe-in-pipe" was changed into the plate one.Bench tests of energy efficiency of the thermal system operation were conducted. Indicators of energy efficiency of the system with the improved RPH were determined, the analysis was performed by comparing with analogues, described in the literature. It was proved that improvement of the thermal system allowed obtaining the improved indicators of energy efficiency. Bench testing showed that efficiency of the improved thermal system is by ≈17 % higher than efficiency of thermal systems based on the multi-stage RPH.The automatic system of monitoring and control of the thermal system with the use of vibration-frequency sensors for assessment of cavitation process effectiveness was developed. The conducted commissioning works made it possible to determine the possibility of applying the developed automatic system with appropriate software for monitoring and control of the thermal system operation.The obtained data of comparative analysis allow recommending the developed rotor-pulse heat generator as a credible alternative to the used thermal devices in thermal heating systems of industrial buildings

Research and Control of the Purity of Production Hydrogen with a High Degree of Purification When Applying the Electrolysis Method of Production

We conducted experimental studies aimed at determining the purity of hydrogen obtained at the electrolysis installation made by Hydrogen Technologies (Norway) at the pipe plant Centravis Production Ukraine in the city of Nikopol, Ukraine.It was established that the determination of hydrogen purity and the degree of its purification from impurities (nitrogen) in microconcentrations involves two stages of measurements:− research into the presence of nitrogen in the samples of production hydrogen in the microconcentrations of [[N2] 0.001−0.01 % (rough estimate);− research into the presence of nitrogen in the samples of production hydrogen in the microconcentrations of [[N2] 0.001−0.01 % (fine assessment).We determined that the purity of production hydrogen, obtained during research, was 99.9±0.1 %. A given value for purity does not match certification indicators for purity of production hydrogen claimed by the manufacturer to equal 99.9999 %.We analyzed the reasons for the mismatch between the purity of obtained hydrogen and claimed characteristics. A detailed analysis revealed that the possible cause of high nitrogen concentration in hydrogen is the worn piston rings in the stage of compressor pistons, which causes the penetration of nitrogen in microconcentrations into production hydrogen. Piston rings in the compressor's stage were replaced. Repeated studies into purity of production hydrogen indicate that the purity of production hydrogen amounted to 99.99±0.01 %, which corresponds to the hydrogen of grade A

Research Into the Impact of Structural Features of Combustion Chamber in Energy-technological Units on Their Operational Efficiency

The experimental studies of the influence of the degree of masonry development (geometry) and aerodynamics of the combustion chambers (circuits of combustion products removal) on the energy-technological indicators of the processes in the system gas-solid (in combustion chambers) were carried out.The experimental research into the influence of geometry and aerodynamics of the combustion chamber on the energy-technological indicators in the system gas – solid body was conducted at the industrial large-scale fire bench.It was shown that a decrease in the height of the working space of the combustion chamber, equipped with flat flame burners, affects the use of fuel due to heat exchange intensification, including direct convection. The dependence is caused by a decrease in heat losses with flue gases and due to a decrease in losses through the masonry.It was established that at the height of the working space of 800÷1,000 mm of the combustion furnace, fuel consumption decreases by 20÷30 %.The design of the combustion space of the furnace of continuous operation mode was developed. The distinctive feature of the furnace of the developed design is the elimination of discreteness and implementation of the stable continuous operation mode of the heating unit. The longitudinal channels were made on the lateral surfaces of the cars and the furnace along the entire length of the latter, which makes it possible to implement the continuous removal of combustion products from the combustion space through canalized hearth of the cars into the longitudinal lateral channels, made in the walls of the furnace. Additional aerodynamic compaction of the working space of the furnace is ensured at any speed of the motion of the cars.It was found that energy-technological efficiency at the arch heating of the combustion units with flat flame burners and combustion products removal under the workpiece (lower smoke removal) is on average by 1.3 times higher than at use of the circuit of products removal above the workpiece (lateral smoke removal), which is used in currently operating furnaces.The design was developed and the tunnel furnace was put into operation. It was for chemical and thermal treatment of metallic and non-metallic materials and products during their heating by the assigned schedule