Unit for automatic calibration of gas flow rate controllers

A unit is described for automatic calibration of gas flow controllers, within which there is a reference flowmeter device ERU-0.5, making it possible to measure gas working medium flow rates of 0.01–0.5 cm³/sec with a total error of ± (0.3–0.7)%. The operating principle of the construction, a procedure for determining gas mass flow rate, the main parameters of the flow rate device, and measurement errors are considered.     

Scope for replacing the prototype kilogram by an atomic mass unit

The main versions of the redefinition for the international prototype kilogram are examined for best accuracy and transmitting the mass unit. It is concluded that it is most promising to use Avogadro’s number and the atomic mass unit in order to transfer to a new standard for the kilogram, i.e., to introduce an atomic kilogram. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 3–5, October, 2006.     

State special standard for the unit of ultrasonic power in water

Work is considered for creating a national standard for the unit of ultrasonic power in water and its construction, metrological characteristics and the results of key international comparisons are provided. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 3–7, March 2006.     

Working standard of the unit of gas flow in a vacuum VÉT 49-2-2006

The working standard for the unit of gas flow in a vacuum VéT 49-2-2006 is described. The composition of the standard and metrological characteristics are provided. A local verification scheme is given for the measurement provisions of gas flow in a vacuum. __________ Translated From Izmeritel’naya Tekhnika, No. 3. pp. 45–48, March, 2007.     

Turbomachinery for small solar power plants

Conversion of solar energy into mechanical or electrical energy in small solar power plants (10–500 kW) requires new design criteria, especially with regard to turbomachinary. The cycles suitable for solar power production are affected by many variable such as kinds of working fluid, range of power and maximum cycle temperature determined by the type of collector. Also, the size of the plant will influence the selection of the various components of the plant, especially that of the turbomachinery. A study of a suitable thermodynamic cycle and working fluid is done for diffèrent ranges of power and temperature. The working fluids considered are steam, toluene, and refrigerant 113 for the Rankine cycle systems and air for gas turbine systems. For Rankine cycles, turbine selection is a problem in the small power range. This is mainly due to the fact, that for high efficiency the enthalpy drop should be as high as possible, and the mass flow rate of the working fluid through the turbine becomes very small. This, in turn, requires high rotational speed, multistaging and partial admission, especially if water is the working fluid. Toluene offers better design criteria for the turbine in the same temperature and power range (50–200 kW). For the very small range (10 kW) refrigerant 113 or similar should be used, otherwise severe design problems with the turbine will occur. In this power range, photovoltaics may also be considered. For high concentration systems with “Brayton cycles” (800–1000°C) only open-cycle gas turbine plants should be used.     

Experimental investigation of the mixing performance of a lobed jet flow

An experimental investigation of flow in a turbulent isothermal air lobed jet is presented. A lobed jet is compared, in the near field, with an isothermal axisymmetric jet with the same exit Reynolds number in terms of dynamics and mixing enhancement. It was found that the streamwise variation of the volumetric flow rate is characterized by a slope is more than twice larger than that for the reference circular jet. This high entrainment rate is governed, at the same time, by the turbulent structures generated by the asymmetric shape of the nozzle and by the high convection in these structures induced by the inner and outer penetration angles of their lobes. Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 1, pp. 102–107, February–March, 2008.     

The use of an ultrasonic measuring system to construct a working standard of air flow speed

Some features of the use of the ultrasonic method of measurement to construct a working standard of air flow speed are considered. It is shown that alternate probing of the flow in both directions is promising and it is thereby possible to reduce the random errors of measurements of its speed. The results of a measurement of air flow speed, obtained using an ultrasonic measuring system and a laser Doppler anemometer are compared. __________ Translated from Izmeritel’naya Tekhnika, No. 12, pp. 35–38, December, 2007.     

Numerical study of effect of oxygen fraction on local entropy generation in a methane-air burner

This study considers numerical simulation of the combustion of methane with air, including oxygen and nitrogen, in a burner and the numerical solution of local entropy generation rate due to high temperature and velocity gradients in the combustion chamber. The effects of equivalence ratio (Φ) and oxygen percentage (γ ) on combustion and entropy generation rates are investigated for different Φ (from 0.5 to 1.0) andγ values (from 10 to 30%). Combustion is simulated for the fuel mass flow rate resulting in the same heat transfer rate (Q)y to the combustion chamber in each case. Numerical calculation of combustion is performed individually for all cases with the use of the Fluent CFD code. Furthermore, a computer program has been developed to calculate the volumetric entropy generation rate and the other thermodynamic parameters numerically by using the results of the calculations performed with the FLUENT code. The predictions show that the increase of Φ (or the decrease of λ) significantly reduces the reaction rate levels. Average temperature in the combustion chamber increases by about 70 and 35% with increase ofγ (from 10 to 30%) and Φ (from 0.5 to 1.0) respectively. With increase ofγ from 10 to 30%, volumetric local entropy generation rate decreases by about 9 and 4% for Φ = 0.5 and 1.0 respectively, while total entropy generation rate decreases exponentially and the merit numbers increase. The ratio of the rates useful energy transfer to irreversibility therefore improves as the oxygen percentage increases     

Generalization of volt-ampere characteristics of the electric arc in a double-jet plasmatron with tubular single-chamber electrode units

On a double-jet plasmatron with cylindrical single-chamber electrode units, an experimental study of volt-ampere characteristics of the electric arc is conducted at current 105–550 A, voltage 400–1320 V, total flow rate of the plasma-forming gas (air) (0.76–9.83)∙10⁻³ kg ⁄ s, angle between the cathode and anode parts 45–62°, distance between the cathode and anode axes at the outlet from nozzles 0.07–0.2 m, and outlet pressure of ~0.1 MPa. Correlations for these characteristics are obtained.     

Dynamic and metadynamic recrystallization of Hastelloy X superalloy

Hot compression tests in the temperature range of 900–1150 °C and strain rates varying between 0.001 and 0.5 s⁻¹ were performed on Hastelloy X superalloy in order to investigate the kinetics of hot deformation. An Arrhenius-type equation was used to characterize the dependence of the flow stress on deformation temperature and strain rate. The results showed that dynamic recrystallization (DRX) as well as metadynamic recrystallization (MDRX) occurred during hot working. A novel technique has been developed for calculating the DRX kinetics parameters on the basis of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) and isothermal transformation rate equations. The variation of grain size in the DRX and MDRX regimes correlated with the standard Zener–Hollomon parameter.     

The use of international standards in the new national standard on the procedure for checking working resistance thermometers

Proposals for a new Russian standard on the procedure for checking working resistance thermometers, connected with changes in the international standards, in particular, in the last edition of the IEC 60751 standard, are considered. The need for a transition when checking from an estimate of the error to an estimate of the uncertainties is demonstrated. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 47–51, September, 2007.     

Some regularities and models in heat transfer theory

The results reported pertain mainly to the classical or “fundamental” sudivisions in the theory of heat and mass transfer. They correspond to the laminar mode of flow, which is considered to be a subject explored in detail owing to advances in computational mathematics. The laminar mode has turned out to be most important and interesting in creating a new generation of gas-turbine power plants distinguished by high efficiency (∼60%) and specific power per unit flow rate of air (∼1 MJ/kg). The thesis is confirmed that applied scientific-engineering developments give a powerful impetus to the formulation of fundamental studies and often determine the trend of the search for physical regularities. Being confined by the framework of a plenary report, we could not touch on all the aspects of the studies devoted to gas-turbine plants conducted at the Institute of High Temperatures of the Russian Academy of Sciences. Some of the results obtained have been published [1–5], while others another are being prepared for publication. Doctor (Eng.) A. F. Polyakov, Candidates (Eng.) D. S. Mikhatulin, R. B. Kuz'min, D. L. Reviznikov, I. V. Repin, and V. V. Rusakov, as well as A. Yu. Varaksin and D. G. Seredovich have contributed to preparing the present report. Institute of Technical Thermophysics of the National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 69, No. 6, pp. 885–896, November–December, 1996.     

The state primary standard for the unit of mean laser power

An upgraded state primary standard is considered for the unit of mean laser radiation power. The technical characteristics and working principle are given. __________ Translated from Izmeritel’naya Tekhnika, No. 7, pp. 3–6, July, 2007.     

Volumetric rate of a turbulent newtonian fluid flow in a cylindrical channel

A new formula to calculate the volumetric rate of a turbulent Newtonian fluid flow is suggested. Experimental verification of the validity of the formula for fluids of different physicochemical nature passed through a cylindrical channel of a laboratory rig has been made. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 5, pp. 856–859, September–October, 2008.     

Influence of stefan flow on the characteristics of heterogeneous combustion of a carbon particle in air

The influence of Stefan flow and radiation-induced heat losses on the characteristics of stationary high-and low-temperature stable and critical regimes of heat and mass transfer of a carbon particle in air is analyzed. The investigations are sponsored by the International Fund “Vidrodzhennya” within the framework of the program ISSEP (contract No. K6V100). Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 146–152, January–February, 1997.     

Simulation of the internal dynamics of solid-fuel rocket engines on the basis of the STAR-CD suite

Flows in the channels of solid-fuel charges with cross sections having different views in plan and flows in the prenozzle volume and the nozzle unit of a solid-fuel rocket engine have been simulated on the basis of the STAR-CD suite for different types of charges and different designs of the input part of the engine nozzle. The influence of the compressibility, turbulence, geometric factors, and flow rate on the distributions of gasdynamic parameters in the working region of the engine has been investigated. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 4, pp. 50–56, July–August, 2006.     

Minimization of air pollutants emissions by process improvement of catalytic reforming unit in an Iranian old refinery

The old oil refineries are largest chemical industries that are responsible for emission of several pollutants and GHGs. It is possible to minimize energy usage as well as air pollution by some process modification. The main objectives of this investigation were the minimization of air pollution and CO₂ emissions in catalytic reforming unit in an oldest and largest refinery in Iran. To assess the air quality, ten sampling stations were selected for measurement of CO, H₂S, SO₂, and PM₁₀ in ambient air. Also concentrations of C₁–C₅, H₂S, and CO₂ were measured in selected unit. In final, structural and process flaws were identified by analyzing real functional circumstances and they were modified. Results show that SO₂, H₂S, and PM₁₀ concentrations are higher than ambient air standard levels in all seasons. Also, according to achieved results, the cold separator gas flow rate is reduced from 38,936 kg/day (once-through gas process) to 9,649 kg/day (recycle gas process). Beside CO₂ and SO₂ emission rates will be reduced 1803 and 136.5 kg/day in this unit, respectively. Furthermore, the modification of this process causes prevention of 1654 kg CO₂ emission into the atmosphere, during each coke burning and catalytic regeneration.     

Some problems in providing the unit of measurement of signal power ratios in the microwave band

The main problems in drawing up standard documentation and developing promising methods of checking the working standards of attenuation at high frequencies and microwave frequencies by analyzing the functioning of systems for providing the unit of measurement in the area of attenuation at high frequencies and microwave frequencies and the technical characteristics of the working standards are formulated. Translated from Izmeritel'naya Tekhnika, No. 10, pp. 45–48, October, 1999.