The Laboratory of Hydraulics

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Часть 1

Laboratories

There are several laboratories at the building department and the best of them is the laboratory of the Chair of Mechanics of Engineering. It is one of the best equipped laboratories in the institute and the students of almost all the departments have their practical training there.

The Laboratory of the Chair of Mechanics of Engineering

The laboratory conducts experiments to test strength of mate­rials. Through these experiments students get acquainted with such mechanical properties of materials as strength, hardness, plasticity, elasticity, shock resistance etc.

The laboratory also conducts experiments to check certain the­oretical statements.

To study mechanical behaviour of materials it is necessary to create stresses changing in time and conditions under which one can get that or another type of deformation.

All this is accomplished by means of testing machines of va­rious capacities the laboratory is equipped with. The laboratory has devices capable of producing deformations ranging in tension with stresses from 1 kg to 50 tons and in compression with stres­ses up to 300 tons. It also possesses devices testing materials for torsion, cold bending, impact fatigue as well as surface hardness.

When materials are tested deformations hardly ever reach the values that can be measured directly. As a rule the values are .exceedingly small and amount to thousandths of a millimeter.

For measuring such small deformations special sensitive extensometers are employed. These may be of mechanical, optical, and electric type, the last type being most widely used in the la­boratory.

There is also a small workshop providing the laboratory with test specimens. It also makes repairs of the testing machines when necessary.

The laboratory is subdivided into two separate parts, one hous­ing the machines for students work and the other being used by the science workers of the chair for their research.

The Laboratory of Hydraulics

The laboratory of hydraulics plays an important role in train­ing specialists at UFU.

The students of most specialities of the Mechanical, Chemical, Heat-Engineering, the Technology of Silicates and the Building departments (all specialities but the Architecture) are given prac­tical training in this laboratory. The laboratory is designed mainly for practical work in the subjects of "Hydraulics" and "Hydraulic Machines".

The laboratory and its equipment are used not only for student work but also for research conducted by science workers of various chairs of the university.

Hydraulic is the branch of science that deals with the laws it balance and motion of liquids in natural and artificial chan­nel structures and machines. It is a part of hydromechanics. The subject of hydraulics and hydraulic machines consists of two parts namely the theoretical part studying the laws of motion and balance of liquids and the practical part concerned with the application of these laws in solving various practical problems.

Methods of differential and integral calculus as well as the laws of physics and theoretical mechanics and some parts of "Strength of materials" form the basis of the subject of "Hydrau­lics and Hydraulic Machines".

The laboratory work and experiments are of great value when studying hydraulics because of the complexity of many hydraulic phenomena which are to be considered in solving certain engi­neering problems. Hydraulics like most sciences can develop only as a result of close combination of theory and experiment. That is why future engineers should acquire not only theoretical knowledge but the skill in conducting laboratory experiments as well. Besides, many phenomena referred to in lectures become clear only after direct observation in the laboratory conditions.

The laboratory is equipped with a reservoir, a pressure tank, a number of working pumps, with two systems of pressure con­duits of different diameters as well as with measuring tanks and receiving chutes. All these are fitted with special measuring devices.

The floor space of the laboratory and the chair is 354 sq. m. All the installations operate at a constant pressure in the following cycle: the reservoir — the centrifugal pump — the pressure tank— the installations-the reservoir.

The most important-laboratory experiments carried out by the students are:

1. The measuring of hydrostatic pressure in an enclosed space. In conducting, the work the students get acquainted with various kinds of devices used for measuring pressure and with the me­thods of their application.

2. An experiment showing the equation of Bernoulli.

3. The conditions (regimes) of motion of liquids. The work shows the difference in the laminar and turbulent flow of a liquid.

The students get to know the way of checking up the operation of hydraulic systems by of Reynolds criterion.

Some experiments show how to determine the coefficient ofhydraulic friction and the coefficients of losses arising in the flow passing through various local obstacles such as turns, valve and sudden narrowing and widening of a channel resulting in the change of either direction or magnitude of the flow or both.

Some other experiments help the students find out both the operation data of a centrifugal pump and the principles of its design and operation.

All these experiments enable the students to improve their knowledge of hydraulics as well as to get certain skill in making various experiments and in describing the results obtained during the work in a short but technically correct summary.