25-03-2011, 04:08 PM
PRESENTED BY:
SACHIN MAHENDRU
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DESIGN OF ENERGY SYSTEM
• Streamlines
• Bernoulli Equation Applications
• Stagnation tube
• Pitot tube
• Free Jets
• Orifice
• Venturi
• Sluice gate
Sharp-crested weir
• Water is flowing with a velocity of 15 m/s and under a pressure of 300 kPa .If the height above datum is 30 m .calculate Total Energy per unit weight of water
• Ans 72 Nm/N
• A 7.5 cm diameter hose contains water flowing at the rate of 0.085 m3 /s . If the Pressure within pipe is 70 KPa gauge ,work out the maximum height to which the water may be sprayed ?
• 26.01m
• A pipe 12.5 cm in diameter is used to transport oil of relative density 0.75 under a pressure of 1 bar .If the total energy relative to datum plane 2.5 m below centre of pipe is 20 Nm/N, Work out the flow rate of oil.
• ANS .1074
• The rate of water through a vertical conical draft tube of a kaplon Turbine is 17.5 m3/s.The Diameter of the draft tube on the side connected to outlet of turbine runner is 2.5 m and the average velocity at exit is 1.5 m/s .if pressure at inlet is not to be less than -.7 Bar and at outlet .12 Bar .how far the tube should exrtend above tail race .presume that exit of draft tube is 1.2 m below tail level
• Ans 6.595
• A horizontal water pipe of diameter 15 cm converges to 7.5 cm diameter . If the pressures at the two sections are 400 kPa and 150 Kpa calculate the flow rate of water
• A pipe 12.5 cm in diameter is used to transport oil of relative density 0.75 under a pressure of 1 bar . If total energy relative to datum plane is 2.5 m below the centre of pipe is 20 Nm/N, work out the flow rate of oil.
Laminar and Turbulent Flows
• Critical Reynolds number (Recr) for flow in a round pipe
Re < 2300 Þ laminar
2300 ≤ Re ≤ 4000 Þ transitional
Re > 4000 Þ turbulent
• Note that these values are approximate.
• For a given application, Recr depends upon
– Pipe roughness
– Vibrations
– Upstream fluctuations, disturbances (valves, elbows, etc. that may disturb the flow)
Minor Losses
• Piping systems include fittings, valves, bends, elbows, tees, inlets, exits, enlargements, and contractions.
• These components interrupt the smooth flow of fluid and cause additional losses because of flow separation and mixing
• We introduce a relation for the minor losses associated with these components
Piping Networks and Pump Selection
Two general types of networks
– Pipes in series
• Volume flow rate is constant
• Head loss is the summation of parts
– Pipes in parallel
• Volume flow rate is the sum of the components
• Pressure loss across all branches is the same
Head Loss due to Sudden Changes in Area of Flow
Sudden Expansion: The head loss at a sudden expansion is given by the expression:
Sudden Contraction: The head loss at a sudden contraction is given by the expression:
• At a sudden enlargement of water line from 24 cm to 48 cm diameter pipe ,the hydraulic gradient rises by 1cm .calculate the rate of Flow
• A horizontal pipe ,10 cm in diameter , is joined by sudden enlargement to a 15 cm diameter pipe .Water is flowing at the rate of 2 m^3/min.Find the loss of head due to abrupt expansion and pressure difference in two pipes. If change of section is gradual without any loss, what would be change in pressure?
• Oil of specific gravity 0.8 flows in a 8 cm diameter pipeline . A sudden expansion takes place into second pipeline of such diameter that maximum pressure rise is obtained .if oil flow rate through the pipeline is 12.5 litres / sec find
1. The loss of energy in sudden expansion in centimeters of oil
2. The differential gauge length indicated by an oil mercury manometer connected between two pipes
• Oil of specific gravity 0.8 flows in a 8 cm diameter pipeline . A sudden expansion takes place into second pipeline of such diameter that maximum pressure rise is obtained .if oil flow rate through the pipeline is 12.5 litres / sec find
1. The loss of energy in sudden expansion in centimeters of oil
2. The differential gauge length indicated by an oil mercury manometer connected between two pipes
• A 15 cm diameter pipe is attached to a 10 cm diameter pipe by means of a flange in such a manner that axes of the two are in straight line .Water flows through the arrangement at a rate of 2m^3/min The pressure loss at the transition as indicated by differential gauge length on mercury manometer connected between the two pipes equals 8 cm .calculate the head loss and coefficient of contraction
• A horizontal pipeline 15 am in diameter is joined by sudden enlargement to 25 cm diameter .Measurements indicate that when flow from smaller cross section ,the head loss is 0.5 m in excess of that when flow takes place from larger to smaller section .Determine the flow rate .Take coefficient of contraction Cc =.63
• When a sudden contraction is introduced in a horizontal pipeline from 50 cm diameter to 25 cm diameter,the pressure changes from 105 kPa to 69 KPa .If coefficient of contraction is assumed to be 0.65 , calculate the water flow rate .
The contraction is subsequently followed by a sudden enlargement from 25 cm section to 69 kPa ,work out the pressure at 50 cm enlarged section
Take specific weight of water =10kn/m3
• When a sudden contraction is introduced in a horizontal pipeline from 50 cm diameter to 25 cm diameter, the pressure changes from 105 kPa to 69 KPa .If coefficient of contraction is assumed to be 0.65 , calculate the water flow rate .
The contraction is subsequently followed by a sudden enlargement from 25 cm section to 69 kPa ,work out the pressure at 50 cm enlarged section
Take specific weight of water =10kN/m3