Experimental Studies of the Heat Exchange Between the Water Film and the Casting Roller in the Thermal Preconditioning Chamber

When the casting roller is cooled or heated in the preconditioning chamber the water is supplied to its surface by flat-jet nozzles. The visual inspection of the model of the casting roller showed that a considerable part of it can be covered with the water film spreading from sprinkling zones. It was established that the heat conductivity in the roller body is considered to be a crucial thermal preparation factor in the conjugate heat-exchange problem for the roller of a large diameter at Bio criterion values exceeding 20. Hence, it is sufficient to provide an essential level of the heat transfer that corresponds to the heat transfer coefficient of 2000 W/(m2∙K) to provide appropriate operating conditions for the thermal preparation of the roller. The conditions are also met in sprinkling zones. Due to this fact this scientific paper studies the heat exchange conditions under the water film that spreads between the adjacent sprinkling zones. A range of changes in the flow rate of the spreading water film was determined experimentally. The conditions of heat exchange between the surface of alpha-calorimeter and the water film were analyzed depending on its flow rate and the heat meter surface temperature. A generalized correlation equation was derived. It was established that the heat exchange intensity in sprinkling zones and under the spreading water film meets technological roller treatment conditions in the preconditioning chambers. The obtained research data can be used for the rational arrangement of the collectors and flat-jet nozzles in casting roller preconditioning chambers to reduce the cold and hot water consumption and cut down operating costs.

Improvement of the technological process of manufacturing bearing grades of steel at the 370/150 mill.

The actual problem of obtaining long products from bearing steel grades with specified microstructure characteristics is considered. The analysis of the capabilities of the existing equipment – a heating furnace and a rolling mill 370/150 of OJSC “BSW – Management Company of the Holding “BMC” was carried out in order to introduce technical measures aimed at reducing carbide heterogeneity in products made of bearing steel grades on the example of steel grade 100Cr6.The influence of different modes of preliminary thermal preparation of continuously cast billets from bearing steel grades on the carbide inhomogeneity in the finished rolling is studied. According to the results of the research, the optimal mode of heat treatment of a continuously cast billet was determined, which allows to produce rolled products that meet the highest requirements of consumers.

PECULIARITIES OF DETERMINATION OF FUEL CONSUMPTION AND EMISSIONS OF HARMFUL SUBSTANCES OF ENGINES OF VEHICLES OPERATING ON GAS FUEL

The article considers the features of the method of research of fuel economy and environmental performance of vehicles with engines converted to run on gas fuel, which are equipped with a thermal training system based on a thermal accumulator phase transition, which is based on the implementation of system interaction of three interconnected components: information, analytical and energy. The schematic diagram of the system of thermal preparation and the information system of estimation of ways of maintenance of thermal preparation of vehicles in the conditions of operation by means of system of thermal preparation on the basis of an onboard complex (Intelligent transportation system) are presented. The peculiarity of the proposed system is that the subsystems create a common information field of the vehicle monitoring system with the heat treatment system, but operate separately from each other, based on the characteristics of the tasks they perform. Improved is the method for determining and calculating fuel consumption and emissions in exhaust gases of vehicles with engines converted to run on gas fuel, equipped with a thermal accumulator phase transition in the processes of pre-start and post-start heat treatment based on the selected model of the engine "Neutralizer". To ensure thermal preparation of vehicles with engines converted to run on gas fuel, equipped with a thermal training system based on a thermal accumulator of the phase transition, a cycle of thermal preparation in operating conditions has been developed. The influence of the thermal preparation system with the heat accumulator of the phase transition of a vehicle with an engine converted to run on gas fuel on the fuel efficiency indicators and environmental indicators in the pre-start and post-start-up processes is established.

JUSTIFICATION OF THE APPLICATION OF THERMAL PREPARATION ON CARS IN DIFFERENT CLIMATE ZONES

The paper presents the rationale for the feasibility of using an autonomous liquid heater for thermal preparation of the engine in different climatic zones. A comparison is made of operating costs when using an autonomous liquid heater and a car alarm with the function of maintaining the optimum temperature. Several large settlements of the Tyumen region were selected for a comparative calculation. Using climatic portals, the average number of cold days over three years was selected and the number of cold engine starts in each city was determined. The objects of the study were Toyota Land Cruiser Prado cars with different power plants: diesel and gasoline. The calculation does not consider the effect of the autonomous heater on the comfort of use and the technical condition of the vehicle, only the current fuel costs during daily operation are taken into account. In the course of the calculations, it was found that at ambient temperatures up to -150C for a gasoline car and -170C for a diesel car, the use of a pre-starting autonomous liquid heater is not economically viable. The required number of days is also determined to obtain economic benefits from the pre-heater, taking into account the cost of its installation on cars with gasoline and diesel engines. Using the results of the study, it can be concluded that not in all settlements it is advisable to install preheaters. The severity of the climate in some cities does not pose a big threat to a guaranteed cold engine start and may be limited only by using the remote engine start function built into the security system.