Final answer:
Vortex casing is not a standard component of centrifugal pumps, while volute casing and casing with guide blades are.
Therefore, the correct answer is: option 2). Vortex casing
Step-by-step explanation:
Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow.
The rotational energy typically comes from an engine or electric motor. They are a sub-class of dynamic axisymmetric work-absorbing turbomachinery.
In the design of centrifugal pumps, the vortex casing is not a commonly used term or a standard component.
The primary components of a centrifugal pump typically include the volute casing, which is designed to convert kinetic energy into pressure by means of a gradually expanding spiral section, and the casing with guide blades, which may refer to the diffuser that uses fixed vanes to direct flow.
Impellers is the rotating component in a centrifugal pump which is equipped with vanes or blades which rotate and move fluid within the pump.