Criteria S.I. Engine (Petrol or Spark Ignition Engine) C.I. Engine (Diesel or Compression Ignition Engine) Working Cycle Works on Otto Cycle or Constant Volume Cycle. Works on Diesel Cycle. Mixture During Suction Stroke Takes a mixture of air and petrol during the suction stroke. Takes only air during the suction stroke. Fuel Used Uses petrol as fuel. Uses diesel as fuel. Compression Ratio Has a compression ratio that varies from 6 to 10. Has a compression ratio that varies from 16 to 20. Engine Weight and Cost S.I. engines are lighter and cheaper. C.I. engines are heavier and costlier. Initial Cost Initial cost is lower compared to C.I. engines. Initial cost is high due to high compression ratio. Starting Starting is easy. Starting is difficult, especially in cold conditions. ...
CLASSIFICATION -
1.) Liquid - it occupy definite volume eg:- Water ,oil ,honey , glycerine , paint , blood etc.
2.) Gas including vapour- it do not occupy definite volume , it has ability to take the shape of the vessel containing them.
TYPES OF FLUID- it has 2 types
1. IDEAL FLUID - The fluid which are incomprehensible and have no viscosity and surface tension . These fluid are not exist because they are imaginary fluid.
2. REAL FLUID -The fluid which has fluid properties such as Viscosity , surface tension and compressible.
These fluid are further classified as follows:-
a.) Newtonian fluid - The fluid in which shear stress is directly proportional to the rate of shear strain . This fluid follow's Newton law of viscosity.
b.) Non- Newtonian fluid- The fluid in which shear stress is not proportional to the rate of shear strain.
C.) Ideal plastic fluid - The fluid in which shear stress is more than yield stress value and shear stress is directly proportional to the rate of shear strain.
d.) Thyrotropic Fluid - the fluid in which shear stress is more than yield stress value and shear stress is not proportional to the rate of shear strain.
Eg:- Printer's ink
VELOCITY GRADIENT = dv/ dy