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_МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «СИМВОЛ НАУКИ» №10-2/2016 ISSN 2410-700Х_
ТЕХНИЧЕСКИЕ НАУКИ
УДК 64.066.8
S.N. Alekhin,
Candidate of Engineering Sciences / Associate Professor
A.S. Alekhin,
Candidate of Engineering Sciences / Associate Professor
N.A. Dmitrienko, Candidate of Pedagogic Sciences/ Associate Professor
T.A. Duloglu graduate student
Institute services and entrepreneurship (branch) Don state technical University
city of Shakhty E-mail: [email protected]
DYNAMIC PROCESSES OF WASHING MACHINES AT DISPERSAL OF EXTRACTION PERIOD
Abstract
Article is devoted to reducing vibro activity of washing machine in the on/off modes. It was revealed that the value of the resonant vibrations mainly affects the growth rate of the perturbation frequency.
Keywords
Washing machine, vibro activity, dynamic loads, resonant oscillation, phase
Modern trends in the development of washing machines are characterized by an increase in the intensity of the washing process and spin, the growth rate of the working bodies and appropriate loads on the supporting parts of the machines which is known to be in the first place, at a centrifugal extraction as it reduces the reliability of the washing machine, increasing energy consumption and maintenance costs, as negative impact on operating personnel.
The most significant dynamic loads occur in the accelerating period and stop the drum of the washing machine at a centrifugal extraction of textiles.
A number of scientific publications is devoted to questions of dropping vibro activity of washing machines in the on/off modes, including, single questions which are considered by Makhov [1], Ryabinky [2], etc. The analysis of dynamic processes proceeding in the on/off modes is considered also in certain papers concerning the theory of oscillation ([3], [4], [5], etc.).
The analysis of scientific literature showed that dynamic process in washing machines at dispersal and a stop modes of a drum is considered, generally as the compelled oscillation of a suspended part (washing knot) with elastic and dissipative system of a vibration insulation, causing misbalance of textile products.
At the same time authors of the papers specify that to drop resonant oscillation at dispersal, we need to reduce its period by increasing the speed of dispersal (increase of rotary speed [6]) of a drum.
So, authors of the published work [6], in particular, specify that reduction of the loadings which are transferred to the supporting designs in the on/off modes that can be reached by means by increasing relation of angular speedup of s to a square of angular frequency due to fluctuations of the vibro- isolated ю2 installation modes. The more this relation is, the smaller value will be reached by the maximum amplitude of fluctuations of the vibro isolated system when passing through a resonance.
In work [3] the author also points out that transition through a resonance smaller amplitudes of fluctuations may be developed, it happens more often at stationary resonant mode as the energy necessary for rocking the system is brought only during a short period.
Growth rate of frequency of indignation [3] is characterized by value q:
МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «СИМВОЛ НАУКИ» №10-2/2016 ISSN 2410-700Х
Q
q =
4c
where Q - is the frequency of oscillation of system;
c - is the frequency of the revolting force changing at dispersal from initial value at t=0 co=0 to the frequency of the established movement Cstat.
The more is the q, the less speed increasing frequency of the revolting force may be. Calculations show that the quicker is a dispersal, the less maximum scope of fluctuations it has and the more instant frequency with which they can reach.
The frequency of the disturbance, at which the maximum (resonance) deviations cr system is determined with the approximate formula:
® p =Q
i ± 1
1 + 0'14^2nq У
3 4q
\ n y
where 5 - is logarithmic decrement of system.
The signs "+" or "-" is in a formula belong, respectively, to increase or drop of frequency of indignation.
From a formula Cp we can come to a conclusion about the influence of growth rate of q (frequency of indignation) on the size of resonant fluctuations and it is also confirmed. At the same time, the author of work [3] specifies that these calculations are made for system without attenuation.
Similar conclusions, but in more detailed consideration are given in Ryabinky's thesis [2].
As a result, taking into account such approach to a question of dropping resonant oscillation based on the accelerated dispersal of a drum of washing machines at an extraction, we may have a paradoxical and contradictory situation consisting in the following.
Manufacturers of washing machines began to install electric motors on the drive of the drum with the starting characteristics allowing to provide its short running start. As observations demonstrated the process of an extraction, in modern washing machines sometimes a dispersal of a drum may happen for about 1 ... 2 seconds, usually no more, excepting r the cases caused by extremely adverse apportion of textile products on the feed well of a drum and the revolting forces arising at the same time are significant.
As a result of it, at the time of beginning dispersal of a drum to driving torque from a shaft of the engine leads to sharp starts the rotation of the drum that practically comes down to a sharp push in the form of reduced time power to the impact on washing knot of the machine caused by reciprocal power reaction from textile products. Under certain conditions short-term power impact on system can be considered as blow [3].
Respectively, it may happen because of the washing knot of the machine as it is suspended vibro isolated part, and at the initial moment it adds equilibrium state that leads to the fact that oscillatory processes of system at dispersal of a drum happens in the transitional mode, characterized by simultaneous participation of a suspended part in two types of oscillations:
X = X1 (t)+ X2 (t)
where xi(t)- free damped oscillations of a suspended part caused by an initial deviation of system from equilibrium state at the time of the beginning dispersal of a drum;
X2(t) -compelled fluctuations of a suspended part without fading periodic time caused by centrifugal force from t unbalanced mass of textile products.
In addition, as has been shown above, the acceleration of the drum during the spin cycle is characterized by short run; it is obviously possible that the suspension of the damped oscillations can be superimposed on its resonant vibrations. The consequence of this is the increase in the maximum amplitudes of oscillation of the system during the period of the resonance provided overlay damped frequencies and phases of the forced oscillation frequency, i.e. if they are in phase.
As shown by preliminary studies concerning oscillatory process of washing machines, in some cases we actually observed transients during acceleration of the drum during the spin cycle.
_МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «СИМВОЛ НАУКИ» №10-2/2016 ISSN 2410-700Х_
For the solution of tasks in this contradictory situation, fast dispersal of a drum is necessary, and on the other hand it can be cause by the growth of resonant fluctuations, it is necessary to find, first of all, the most rational design and regime data of the washing machine providing, at least, course of the transitional mode in the conditions of lack of phase synchronism of frequencies in two types of fluctuations. It is one of the most important tasks for further probes of the question to drop vibro- activity of washing machines which is considered in this work at drum dispersal in the extraction period. References
1. Makhov D.P. Development and research of a method of reducing vibro activity drum type washing machine during the spin cycle: thesis ... Candidate of Engineering Sciences: 05.02.13. - Shakhty, 2009. - 200 p.
2. Ryabinky L.M. Research of vibration isolation washer-extractors machines for textiles: thesis ... Candidate of Engineering Sciences/ Ryabinky L.M. - L., 1972. - 153 p.
3. Biderman V.A. The theory of mechanical vibrations. - M.: Higher school, 1980. - 408 p.
4. Babakov I.M. The theory of mechanical vibrations. M.: Dropha, 2004. - 591 p.
5. Ivovich I.A. Onishchenko V.Ya. Protection against mechanical vibration.- М.: Mascinostroenie, 1990. - 272 p.
6. Ivovich I.A. The transition matrix in the dynamics of elastic systems: a handbook. - М.: Mascinostroenie, 1981. - 185 p.
© Alechin S.N., Alechin A.S., Dmitrienko N.A., Duloglu T.A., 2016
УДК 622.691.2-404
Алида Ильфатовна Батршина
студент 2 курса магистратуры факультета трубопроводного транспорта Уфимский государственный нефтяной технический университет, Научный руководитель: Раиса Абубакировна Молчанова, к.т.н., доцент кафедры «Промышленная теплоэнергетика» Уфимский государственный нефтяной технический университет,
г. Уфа, Российская Федерация
СПОСОБЫ РЕГАЗИФИКАЦИИ СЖИЖЕННОГО ПРИРОДНОГО ГАЗА
Аннотация
В данной статье рассматриваются наиболее широко используемые регазификаторы: регазификаторы с водяным орошением, с погружной горелкой, жидкостного типа с промежуточным теплоносителем и атмосферные регазификаторы, а также их преимущества и недостатки.
Ключевые слова
сжиженный природный газ, регазификаторы, морской регазификационный терминал, регазификация,
испаритель.
Введение
Транспортировка природного газа в сжиженном состоянии позволяет диверсифицировать поставки газа и открывает доступ в районы, до которых невозможно проложить трубопроводы. Несмотря на довольно большие затраты электроэнергии на ожижение газа, увеличивающие стоимость СПГ по сравнению с трубопроводным газом, доставка газа дешевым морским транспортом открывает большие перспективы в снабжении потребителей именно этим энергоносителем. СПГ сохраняет все преимущества природного газа, как самого экологичного топлива.
После доставки СПГ к месту назначения его необходимо снова из жидкости превратить в газ. Этот процесс называется регазификацией.
