Grey cast iron with tensile strength of 250 MPa.
The losses in a centrifugal pump are : Friction losses due to eddies in flow, leakage, friction loss due to rotation of impeller in chamber of water, gland and bearing power losses.
The main factors that are responsible for the formation of built up edge are :
At constant capacity, head is proportional to
Geometric similarity is mainly for same shape for model and prototype, kinematic similarity is concerned with streamline pattern, whereas dynamic similarity concerns the ratio of forces.
The approximate constant and continuous power which is assured at power station and would be available throughout the year is called firm power.
In run-of-the river schemes which are generally designed for % availability of water, the firm power would be available for at least % of the years during the life of the scheme. However in some years discharge in the river may be more than % availability discharge and some extra power known as secondary power can be generated.
A polytropic process is one that follows the equation pun = constant (index n may have values from - oc to + oo. This process approaches isobaric when n = 0, isothermal when n = 1, and isometric when n =
Ammonia and CO2 respectively.
Metacentre is the point at the intersection of the buoyancy with the vertical axis of the body.
Overall heat trfer coefficient can be increased by increasing velocity of water in tube. Further steam needs more space due to higher specific volume.
Hard water contains excess of scale forming impurities and soft water contains very little or no scale forming substances.
Moisture, volatile matter, ash and fixed carbon.
The advantages of the Cycloidal gears are as follows:
The advantages of Involute gears are as follows:
Efficiency of a pump (centrifugal) depends on the size, speed, and proportions of the impeller and casing.
In two-stroke engine lub oil is mixed with petrol and thus some lub oil is blown out through the exhaust valves by scavenging and charging air. There is no such wastage in four stroke petrol engine.
Manganese increases tensile strength and hardness. It decreases weldability.
Capillarity : The rise or fall of a liquid in a capillary tube caused by surface tension. The magnitude of rise or fall depends on the relative magnitudes of the cohesion of the liquid and adhesion of the liquid to the walls of the containing vessels. Capillarity is of importance in tubes smaller than 10 mm diameter.
Rise of liquid : Liquids rise (in capillary tube) when they wet and adhesion of the liquid to the walls is greater than the cohesion of the liquid.
Fall of liquid : Liquids fall (in capillary tube) when they do not wet and the cohesion of the liquid is greater than the adhesion of the liquid to the walls.
Jet pumps are easy to maintain and can be used to trport gases, liquids and mixtures of both.
Sulphur in coal gives rise to number of ecological problems ranging from acid mine drainage to ash waste problems and air pollution due to SO2 emission. Emission of S02 is the cause of acid rain and is responsible for severe environmental damage.
Sliding contact bearings can be classified on the basis of the thickness of the lubricating agent layer between the bearing and the journal. They can be classified as follows:
Centre of gravity of body should be located below metacentre.
The energy line is a graphical representation of the energy at each section.
Hydraulic grade line lies below the energy line by an amount equal to the velocity head at the section.
For uniform laminar flow.
Springs can be broadly classified into the following types:
The three functions served by a surge tank are
Vapour pressure is the partial pressure created by the vapour molecules when evaporation takes place within an enclosed space. It becomes important when negative pressures are involved.
The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface and acts through the center of pressure for the vertical projection.
Vertical component of the hydrostatic force on any surface is equal to the weight of the volume of liquid above the area and passes through the e.g. of the volume.
The drill sleeve is suitable for holding only one size of shank. If the taper shank of the tool is smaller than the taper in the spindle hole, a taper sleeve is used.
When the taper tool shank is larger than the spindle taper, drill sockets are used to hold the tools. Drill sockets are much longer in size than the drill sleeves.
These characteristics affect SI engines in cold starting, icing of carburettor and dilution in crankcase respectively.
Hydrostatic paradox is the phenomenon that the floor load of water in vessels of different shapes carrying water at same level depends only on the area of the bottom surface and not on the shape of the vessel.
In rotational flow the vorticity is non zero and in irrotational flow it is zero. In irrotational flow the net rotation of a fluid element about its own mass centre is zero as it moves from one place to another. For it, dv/dx = du/dy.
NO* in gas turbines is controlled by
Thermal neutrons are slow neutrons (having energy below 1 eV) which are in thermal equilibrium with their surroundings.
The economic diameter of a power tunnel is determined such that the total value of following two factors is least
In steady flow.
Rateau and Curtis respectively.
When Prandtl number is equal to unity.
It is the ratio of heat change from feed water to steam and the heat of vaporization of steam at atmospheric pressure.
Due to uneven extension and contraction of belt.
Some of the important cold drawing processes are as follows:
At the critical pressure ratio.
Chromium and nickel.