Centrifugal pumps Impellers Multistage impellers Cross section of
- Slides: 29
Centrifugal pumps
Impellers
Multistage impellers
Cross section of high speed water injection pump Source: www. framo. no
Water injection unit 4 MW Source: www. framo. no
Specific speed that is used to classify pumps nq is the specific speed for a unit machine that is geometric similar to a machine with the head Hq = 1 m and flow rate Q = 1 m 3/s
Affinity laws Assumptions: Geometrical similarity Velocity triangles are the same
Exercise • Find the flow rate, head and power for a centrifugal pump that has increased its speed • Given data: hh = 80 % n 1 = 1000 rpm n 2 = 1100 rpm P 1 = 123 k. W H 1 = 100 m Q 1 = 1 m 3/s
Exercise • Find the flow rate, head and power for a centrifugal pump impeller that has reduced its diameter • Given data: hh = 80 % D 1 = 0, 5 m D 2 = 0, 45 m P 1 = 123 k. W H 1 = 100 m Q 1 = 1 m 3/s
Velocity triangles
Reduced cu 2 Slip angle Friction loss Slip angle Impulse loss Slip Best efficiency point
Power Where: M = torque [Nm] w = angular velocity [rad/s]
In order to get a better understanding of the different velocities that represent the head we rewrite the Euler’s pump equation
Euler’s pump equation Pressure head due to change of peripheral velocity Pressure head due to change of absolute velocity Pressure head due to change of relative velocity
Rothalpy Using the Bernoulli’s equation upstream and downstream a pump one can express theoretical head: The theoretical head can also be expressed as: Setting these two expression for theoretical head together we can rewrite the equation:
Rothalpy The rothalpy can be written as: This equation is called the Bernoulli’s equation for incompressible flow in a rotating coordinate system, or the rothalpy equation.
Stepanoff We will show a centrifugal pump is designed using Stepanoff’s empirical coefficients. Example: H = 100 m Q = 0, 5 m 3/s n = 1000 rpm b 2 = 22, 5 o
Specific speed: This is a radial pump
We choose:
w 2 u 2 cm 2 cu 2
Thickness of the blade Until now, we have not considered the thickness of the blade. The meridonial velocity will change because of this thickness. We choose: s 2 = 0, 005 m z = 5
w 1 u 1 c 1= cm 1
Dhub We choose: Without thickness
Thickness of the blade at the inlet w 1 u 1 b 1 Cm 1=6, 4 m/s
w 2 cm 2=4, 87 m/s b 2=22, 5 o u 2=44, 3 m/s cu 2
w 2 cm 2=4, 87 m/s u 2=44, 3 m/s cu 2
- Centrifugal pumps basics
- Components of a centrifugal pump
- Supply chain drivers and metrics
- Impellers of supply chain
- Common collector
- Multistage sampling
- Multistage sampling
- Multistage sampling example
- Multistage and multihash algorithm
- Time complexity of multistage graph
- Multistage graph
- A swamping resistor in a common-emitter amplifier
- Multistage sampling
- Multistage batch distillation
- Types of coupling in multistage amplifier
- Advantages of multistage amplifier
- Microelectronic
- Total condenser and partial condenser
- Calculate residual income
- Multistage amplifier conclusion
- Uma multiprocessors using multistage switching networks
- Multistage model for e-commerce
- Differential and multistage amplifiers
- Active load differential amplifier
- Multistage sampling
- Cluster sampling
- What is the main advantage of a multistage rocket?
- Multistage graph
- Taenia saginata
- Structure of centrifugal pump