Кафедра "Технологія машинобудування та металорізальні верстати"

Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/3960

Офіційний сайт кафедри http://web.kpi.kharkov.ua/tmms

Кафедра "Технологія машинобудування та металорізальні верстати" заснована в 1934 році. Першим завідувачем кафедри був доцент Ф. К. Корольов – фахівець в області металорізальних верстатів, який беззмінно керував колективом до 1966 року і суттєво вплинув на розвиток кафедри.

Кафедра входить до складу Навчально-наукового інституту механічної інженерії і транспорту Національного технічного університету "Харківський політехнічний інститут".

У складі науково-педагогічного колективу кафедри працюють: 5 докторів технічних наук, 6 кандидатів технічних наук; 5 співробітників мають звання професора, 6 – доцента.

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Determination of the coefficient sliding friction value in the contact the cutting tool-composite
(Національний технічний університет "Харківський політехнічний інститут", 2022) Khavin, G. L.; Hou, Zhiwen
One of the most important characteristics in calculating the cutting tool wear in contact with the processed composite is the friction coefficient. In most calculations, including the finite element method, the friction coefficient is traditionally set as a constant, the value of which is often taken from experience without any reason. However, when machining reinforced composites, there are too many mechanical and technological factors that have a very strong effect on the friction coefficient value. This influence is associated not only with the initial heterogeneity of the composite, but also with the constant actual change in the contact conditions over time, caused by the wear of the tool cutting part. The friction coefficient value in real conditions of contact interaction has a very complex physical content due to the presence of products of fibers and binder destruction in the contact, partial a binder melting at a temperature in contact, and the unevenness of the cut fibers presence. This article presents a formulation that allows you to calculate the value of the friction coefficient depending on the volumetric content and the inclination angle of the reinforcing elements. It is proposed to calculate the friction coefficient value as the product of two factors, one of which is responsible for the filler volumetric content, and the other for the reinforcing elements orientation. The calculations use the mixtures theory relations. The presented expressions for calculations are based on the use of limited experimental information presented by various authors. The available data are often contradictory and relate, as a rule, to predicting the processed surface quality of unidirectional glass and carbon fiber reinforced plastics. At the same time, the friction coefficient value in the calculations has a significant impact on the representation of tool wear and life. The model does not take into account the contact pressure effect, mutual sliding velocity and temperature on the friction coefficient value, which will be the subject of further research in this direction.
Modeling npp power unit steam turbine installation steam separatorsuperheater temperature characteristics by interval analysis methods
(Національний технічний університет "Харківський політехнічний інститут", 2020) Potanina, Tetiana Volodymyrivna; Yefimov, Olexander Vyacheslavovych; Khavin, G. L.
The determination of the temperature characteristics of one of the significant elements of the wet-steam turbines of nuclear power units – the steam separator-superheater is considered: namely the construction of the dependence of the temperature of the heated steam at the outlet of the second stage on the changing load of the power unit. Modeling is carried out taking into account the error limitation without reliable information about its distribution. To evaluate the coefficients of empirical dependence, constructed according to the results of experimental data, it is proposed to use numerical methods of interval analysis. The interval approach allows building a refined tube, guaranteed to contain acceptable dependences of the temperature of the heated steam on the electric power of the power unit. In a situation of data uncertainty and limited errors, numerical methods of interval analysis allow creating models of processes and equipment of NPP units with the maximum possible correspondence to a real object.
The innvestigation of the process streams integration in the multieffect evaporation plant for the concentration of sorghum syrup
(Технологический центр, 2018) Babak, Tatyana; Golubkina, Olga; Ponomarenko, Yevgeniya; Solovey, Ludmila; Khavin, G. L.
The study on the integration of heat streams of the evaporation station for sorghum syrup concentrating is presented. The relevance of the research is is why the research, aimed at reducing the consumption of external energy and enhancing operating efficiency, is relevant and has practical value. The main purpose of the work is to create a scientifically substantiated design with enhanced economic indicators of operation, ensuring saving in consumption of hot utility (steam) and cooling water. The problem was solved using the pinch-analysis. Heat streams, requiring heating and cooling, were identified, and the alternative project based on the selection of the value of minimum temperature difference ΔTmin, was created. This value was calculated and substantiated based on the data on thermal streams. The stream of condensate of return steam, the heat excess of which had not been used so far, was added to the system. For the alternative project, the layout of heat exchange equipment was proposed, calculation of plate heat exchangers was performed. The designed network of heat exchangers made it possible to decrease the annual steam consumption by 18 %. Cost-effectiveness analysis was conducted by comparing the indicators for two of the projects of the syrup preheating department for the evaporation station. The proposed alternative project saves power consumption of cooling water by 35.9 kW, of heating vapor steam – by 60.5 kW. At the interest rate of profit tax of 18 %, implementation of the alternative project will pay off in 4 months. As a result, net annual gain of an enterprise is planned to increase by 16 %, at virtually the same payback period of the projects. Application of the methods of heat streams integration made it possible to develop an effective project of sorghum syrup preheating before evaporation and ensure saving of external utilities.
Advantages of using channels with different corrugation height in the plate heat exchangers
(Технологический центр, 2018) Khavin, G. L.; Babak, Tatyana
In the case when there is a difference in consumption on the side of the cold and hot heat carriers, the use of channels with the same corrugation height in one heat exchanger leads to a decrease in velocity of the heat carrier on the side with low consumption. Low velocity contributes to appearance of deposits on the heat transfer surface, which leads to disruption of operation mode of the apparatus and a forced clean-up stop. In case of using channels with a different corrugation height (cross-section area), velocities in the channels are aligned and intensity of emergence and growth of contamination falls sharply. It also allows us to reduce the heat transfer surface area of the apparatus and fully implement permissible pressure losses on the sides of the heat exchanger. For designing of heat exchangers of this structure, the authors developed the mathematical model that allows making calculations of heat exchangers for assigned operation conditions with the use of geometrical data of the plates, thermophysical properties of heat carriers and criterial equations for plates of the selected type. The calculation algorithm involves determining of the ratio between corrugation heights. Practical value lies in the fact that the proposed approach makes it possible to extend the service life of the heat exchanger prior to a maintenance stop. This enables provision of continuity of the technological process and decreases operation costs. Calculation of the heat exchanger of hot water supply by the parallel scheme of attachment to heating networks and the heat exchanger of stage 1 of the two-stage hybrid scheme was presented. Calculation data indicate a decrease in the heat transfer surface area compared to heat exchangers with channels of equal height, full realization of pressure losses and their alignment in the channels, which facilitates an increase in resistance to contamination of the plates’ surface. Calculation showed the advantage of using apparatuses with channels of different cross-section area. The higher the ratio between consumption of heat carriers in the channels, the stronger this advantage.
Possibility of Heat Pump use in Hot Water Supply Systems
(2016) Babak, Tatyana; Duić, Neven; Khavin, G. L.; Boldyryev, Stanislav; Krajačić, Goran
The problem of modernization of the heat module with two-stage mixing scheme connection of hot water supply by installations of the heat pump during interheating period is considered. Heating water of the in-house circuit of the building heating system is used as a heat source for heat pump. The district cooling of the residential areas is possible through the heaters during the summer. R600 refrigerant is chosen for heat pump for its environmental-friendliness and low-pressure of evaporation and condensation. The economic calculation is made for interheating period comparing the operation with and without heat pump. This paper advances selection of optimum amount of heat to be recovered during low potential heat utilisation and targets for heating and cooling capacities.