1. Classification of lubricants.a. Animalb. Vegetablec. Minerald. Synthetic

2. Any one property of animal lubricants.a. These are highly stable at normal temperatures.b. Animal lubricants may not be used for internal combustion because they produce

fatty acids.3. Examples of vegetable lubricants are:

a. Castor oilb. Olive oil (Zaitoon)c. Cottonseed oil

4. Use of mineral Lubricants:a. These lubricants are used to a large extent in the lubrication of aircraft internal

combustion engines.5. Why need for synthetic lubricants arise?

a. Because of the high operating temperatures of gas-turbine engines, it became necessary to develop lubricants which would retain their characteristics at temperatures that cause petroleum lubricants to evaporate and break down.

b. Synthetic lubricants do not break down easily and do not produce coke or other deposits.

6. What is Viscosity, also write down its measuring unit?a. Viscosity is technically defined as the fluid friction of oil.b. To put it more simply, it is the resistance oil offers to flow.

Dynamic viscosity, also absolute viscosity, the more usual one (typical units Pa·s, Poise, P);

The usual symbol for dynamic viscosity used by mechanical and chemical engineers – as well as fluid dynamicists – is the Greek letter mu (μ).[4][5][6] The symbol η is also used by chemists, physicists, and the IUPAC.[7]

The SI physical unit of dynamic viscosity is the pascal-second (Pa·s), (equivalent to N·s/m2, or kg/(m·s)). If a fluid with a viscosity of one Pa·s is placed between two plates, and one plate is pushed sideways with a shear stress of one pascal, it moves a distance equal to the thickness of the layer between the plates in one second. Water at 20 °C has a viscosity of 0.001002 Pa·s.

The cgs physical unit for dynamic viscosity is the poise [8] (P), named after Jean Louis Marie Poiseuille. It is more commonly expressed, particularly in ASTM standards, as centipoise (cP). Water at 20 °C has a viscosity of 1.0020 cP.

1 P = 0.1 Pa·s,1 cP = 1 mPa·s = 0.001 Pa·s

Kinematic viscosity is the dynamic viscosity divided by the density (typical units cm2/s, Stokes, St).

In many situations, we are concerned with the ratio of the inertial force to the viscous force (i.e. the Reynolds number, ), the former characterized by the fluid density ρ. This ratio is characterized by the kinematic viscosity (Greek letter nu, ν), defined as follows:

The SI unit of ν is m2/s. The SI unit of ρ is kg/m3.

The cgs physical unit for kinematic viscosity is the stokes (St), named after George Gabriel Stokes. It is sometimes expressed in terms of centistokes (cSt). In U.S. usage, stoke is sometimes used as the singular form.

1 St = 1 cm2·s−1 = 10−4 m2·s−1.1 cSt = 1 mm2·s−1 = 10−6m2·s−1.

Water at 20 °C has a kinematic viscosity of about 1 cSt.

The kinematic viscosity is sometimes referred to as diffusivity of momentum, because it is analogous to diffusivity of heat and diffusivity of mass. It is therefore used in dimensionless numbers which compare the ratio of the diffusivities.

7. Write Down some types of Pumps.a. Rotary pumps;

. Gear pump

. Vane pump

. Screw pumpb. Reciprocating pump:

. Piston Pump

. Plunger Pump

. Diaphragm pump.

8. Difference between centrifugal and PD pump.9. Bearing Nomenclature.