Centrifugal Pumps

A centrifugal pump converts the input power to kinetic energy in the liquid by accelerating the liquid by a revolving device - an impeller. The most common type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radially outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump.


The energy created by the pump is kinetic energy according the Bernoulli Equation. The energy transferred to the liquid corresponds to the velocity at the edge or vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is, the higher will the velocity of the liquid energy transferred to the liquid be. This is described by the Affinity Laws.

Pumping Philosophy

Pumping Philosophy

• Pumps transfer liquids from one point to another by converting mechanical energy from a rotating impeller into pressure energy (head)
• The pumping system designer must consider fluid properties, determine end use requirements, and understand environmental condition.
• The fluid properties being pumped can significantly affect the choice of pump, includes;         -Acidity/ Alkalinity (pH) and chemicals composition
         - Operating temperature
          - Solid concentration/particle size
          - Specific gravity
          - Vapor pressure
          - Viscosity

• End use requirement – system flowrate and head: The design pump capacity is needed to accurately size of the piping system, determine friction head loss, construct a system curve, and select a pump and drive motor.

•Process requirement can be met by providing a constant flowrate, or using a throttling valve, or variable speed drive to supply continuously variable flow rate

Heat Balance Diagram for Power Plant

An application of the first law of thermodynamics to a process in which any work terms are negligible.
For a closed system, one that always consists of the same material, the first law is Q + W = ΔE, where Q is the heat supplied to the system, W is the work done on the system, and ΔE is the increase in energy of the material forming the system. It is convenient to treat ΔE as the sum of changes in mechanical energy, such as kinetic energy and potential energy in a gravitational field, and of internal energy ΔU that depends on changes in the thermodynamic state of the material. Because the rates at which any changes occur are usually of interest, heat balances are often written in terms of heat flow rates (heat per unit time), sometimes denoted by a dot over the symbol, , so that for a process with negligible work, kinetic energy and potential energy terms, , the rate of change of internal energy with time.

efficiency boiler

The efficiency of a boiler is quoted as the % of useful heat available, expressed as a percentage of the total energy potentially available by burning the fuel. This is expressed on the basis of gross calorific value (GCV). ASME Standard: PTC-4-1 Power Test Code for Steam Generating Units This consists of • Part One: Direct method (also called as Input -output method) • Part Two: Indirect method (also called as Heat loss method)