Influence of the air Layer Between the Conductor and the Layer Ofinsulating Material in Cable Products

There are developed mathematical model of physical and chemical processes of polymerization adhesive coating stranded cable. There are shown difference in the temperature distribution along the radius of the finished product in the presence of an air gap between the conductor and the rubber sheath. Also, due to the need to change process parameters with possible loose contacts inside the cable. Such as the temperature of the heating surface, feeding speed and dwell time in the oven

Determination of necessary time of measurements of surface thermocouples depending on conditions of technological processes

Researches of nonstationary processes of heating up of sensitive elements of thermocouples by means of one-dimensional and two-dimensional mathematical models of heat transfer are conducted. By the created models are defined duration of heating up of the sensitive elements necessary for achievement of the temperature of the thermocouple within a permissible deviation from rated direct current characteristic for three types of thermocouples – K, L and S. Distinctions in the results received by means of one-dimensional and two-dimensional models of heat transfer are shown and justified. For surface thermo-electric transformers, temperature measurement conditions are simulated in case of different value of air gap between the heater and thermocouple surface. It is shown that the value of a gap has an essential impact on minimum necessary time of measurement. Change of duration of heating up of thermocouple from heatphysical characteristics of the typical materials which are used in the case of manufacture of sensing elements is probed

Determination of necessary time of measurements of surface thermocouples depending on conditions of technological processes

Researches of nonstationary processes of heating up of sensitive elements of thermocouples by means of one-dimensional and two-dimensional mathematical models of heat transfer are conducted. By the created models are defined duration of heating up of the sensitive elements necessary for achievement of the temperature of the thermocouple within a permissible deviation from rated direct current characteristic for three types of thermocouples – K, L and S. Distinctions in the results received by means of one-dimensional and two-dimensional models of heat transfer are shown and justified. For surface thermo-electric transformers, temperature measurement conditions are simulated in case of different value of air gap between the heater and thermocouple surface. It is shown that the value of a gap has an essential impact on minimum necessary time of measurement. Change of duration of heating up of thermocouple from heatphysical characteristics of the typical materials which are used in the case of manufacture of sensing elements is probed

Influence of the air Layer Between the Conductor and the Layer Ofinsulating Material in Cable Products

There are developed mathematical model of physical and chemical processes of polymerization adhesive coating stranded cable. There are shown difference in the temperature distribution along the radius of the finished product in the presence of an air gap between the conductor and the rubber sheath. Also, due to the need to change process parameters with possible loose contacts inside the cable. Such as the temperature of the heating surface, feeding speed and dwell time in the oven

Ignition mechanism and characteristics of gel fuels based on oil-free and oil-filled cryogels with fine coal particles

Methods of preparing heterogeneous gel fuels have been elaborated on the basis of oil-free and oil-filled cryogels, containing coal dust particles with a size no more than 140 μm. Mechanical properties of 20-mm fuel pellets have been analyzed. The ignition mechanisms of heterogeneous gel fuels have been experimentally discovered in a high-temperature (600–1000 °C) oxidizer medium, and the influence of the initial fuel temperature (from −85 to 20 °C) on the fuel ignition characteristics has been researched. The multi-component composition of the oil-filled cryogels with coal dust particles is the reason for microexplosions that leads to the fuel sample dispersion and intensification both the ignition and burnout. Such fuel compositions are characterized by 1.5–2-fold lower ignition delay times (1–6 s vs. 2–12 s) than the compositions based on cryogels containing only coal particles, other things being equal

Oil-filled cryogels: new approach for storage and utilization of liquid combustible wastes

A method of preparing oil-filled cryogels on the basis of an aqueous solution of poly(vinyl alcohol) (PVA) has been elaborated. The stability of primary oil emulsions and their rheological properties were analyzed for 30 days, as well as the mechanical properties of gel fuel pellets (obtained after 15 cycles of freezing/thawing of oil emulsions) with size of 20 mm for a group of compositions: 100-20 vol % aqueous solution of PVA (5, 10 wt %) + 0-80 vol % oil. The rheological behavior of non-Newtonian oil emulsions is described by the Herschel-Bulkley model. The elastic moduli and the tensile strength of fuel pellets of different component compositions range from 0.7 to 7.6 kPa and from 2.5 to 60 kPa, respectively. The oleophilic properties are more distinct for gel fuel prepared from oil emulsions with a higher content of the dispersed phase and lower concentrations of the polymer in the dispersion medium. The ignition mechanism and combustion characteristics have been established for processes occurring under the conditions of a radiant heat supply. Gel fuels, unlike combustible liquids, are characterized by a longer induction period, but a multicomponent structure of fuel caused microexplosions that enhance the combustion process