CE220. Hydraulics I (ects: 6)
THEORY
1.General: Definitions, dimensions and standard measuring units of pertinent physical variables (pressure, pressure force, surface tension, capillary pressure, etc). Physical properties and physical characteristics of liquids and gases (mass density, specific weight, viscosity, vapour tension, compressibility). Transformation of units in different standards. Phenomenological differences between solids, liquids and gases.
2.Hydrostatics: Hydrostatic pressure, pressure measurement, manometers. Hydrostatic forces on immersed surfaces (flat inclined and curved). Determination of pressure center. Hydrostatic forces on vessels, immersed bodies etc. Byonancy and flotation. Stability of floating bodies.
3.Hydrodynamics: Basic concepts of hydrodynamics. Various types of flow in closed and open conduits and pipes (constant, transient/unstable, uniform, two- & three- dimensional, laminar, transient, turbulent flows). Phenomenological differences between laminar, transient and turbulent flows, Reynolds number. Flow path, flow lines, streak lines, stream lines, flow field.
Integral analysis - Balances.
(A) Mass balance and equation of continuity in fixed control volume. Equivalent uniform flow and mean velocity.
(B) Hydraulic energy balance, fixed control volume. Euler (differential) & Bernoulli (integral) representations. Equivalent pressure heights; manometric pressure; dynamic pressure. Piezo/manometric and total head (hydraulic energy per liquid weight) lines. Hydraulic power: basic relations, efficiency ratio of hydraulic machines.
(C) Linear momentum balance - fixed control volume. Hydrodynamic forces on surfaces.
Flows in pipes under pressure (closed conduit flow).
Pipe entrance, entrance length, uniform flow. Velocity and tension profiles in laminar, transient and turbulent flows. Linear energy dissipation. Effect of pipe wall roughness. Darcy-Weisbach relation. Friction coefficient. Moody diagram and Colebrook-White relations. Hazen-Williams relation. Local energy dissipation.
Analysis of simple hydraulic networks comprising composite pipelining, elbows, filters, switches, junctions etc. Basic design principles of hydraulic networks.
Discharge from pipes, vessels and orifices (free and forced).
Hydraulic engines.
General aspects, pumps, turbines. Power-flowrate-head relations. Principal elements in matching a pump to a hydraulic installation. Water hammer effect in pipes and installations
LABORATORY
The laboratory part comprises a set of so called "lab exercises", whereby, basic hydraulic phenomena are reproduced, observed and analyzed under controlled laboratory conditions in "lab classes".
Each laboratory exercise is deployed as follows: basic theoretical analysis of examined phenomenon; description of specific apparatus; laboratory reproduction; identification/description of the prevailing phenomena and mechanisms; data capture (measurements); data analysis; reconstitution of the transfer function of the phenomenon. Each student prepares a short essay with computations, results, remarks, observations, comments and conclusions.
At the end of the semester, students undergo a short written examination.
The set of laboratory exercises is as follows:
1. Density measurement of liquids; pressure measurement - use of manometers and gauges.
2. Hydrostatic forces - determination of pressure center on immersed surfaces
3. Dynamic viscosity - lab measurement of viscosity by means of Stokes analysis of free sink of spheres.
4. Flowrate measurement - use of hydraulic bench and weighing bucket balance.
5. Transient flow - Reynolds number - phenomenology by use of dye and streaklines.
6. Flow in Hele-Shaw cell - dynamic flow.
7. The Venturi principle
8. Flowrate measurement - calibration of various types of lab flowrate meters (Venturi, diaphragm, variable area /rotameter).
9. Measurement of friction losses along a straight pipe
10. Measurement of friction losses along pipes, bends, taps etc.
11. Continuous liquid jet impinging on surfaces.
12. Discharge through orifice.
13. Hydraulic engines (pumps - turbines)
14. Hydrokinetics: Representation of various types of flow. Kinematic similarity representation of shock-waves and supersonic flow.
15. Final written examination.