How do you calculate the velocity of a chimney?
Design velocities of larger furnaces should not exceed 10 m/s. Required chimney area can be calculated as A = Q / v (3) where A = cross-sectional area of chimney (m2) Q = volume of flue gases at chimney temperature (m3/s) v = velocity (m/s) In general 1 kW boiler heat requires 1100 mm2 of chimney area.
How do you find velocity from pressure?
Pressure To Velocity Calculator
- Formula. V = Sqrt [ (2*q/p) ]
- Dynamic Pressure (pascals)
- Fluid Density (kg/m^3)
How is stack velocity measured?
To determine the velocity profile, the average gas velocity and volumetric flow rate in a stack or duct. The method is based on the measurement of the velocity pressure heads and stack gas temperatures. It takes into consideration the stack gas molecular weight, pressure and the configuration of the stack or duct.
Is less than pressure at chimney outlet?
For a very large diameter chimney, the hot air flow through the ceter of the chimney and cold outside air will enter the chimney from outlet. Outlet pressure is less than inlet pressure due to high temperature(less density) of hot gases and vacuum creates downside and fresh air enters.
What is chimney efficiency?
Efficiency of Chimney It may be Defined as the ratio of the energy required to produce the artificial draught (expressed in meters head or J/Kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to the natural draught.
What is a stack calculator?
Navigator is an example of a Menu-Driven user interface. Pressing one of the arithmetic buttons causes the top two numbers on the stack to be replaced by their sum, product, difference, or integer quotient. The PUSH button pushes the number entered in the Top field onto the top of the stack.
What is gas velocity?
That stems from the fact that the gas molecules are moving in all directions in a random way and each random speed in one direction is cancelled out by a molecule randomly moving in the exact opposite direction, with the exact same speed (when the gas sample is considered in a random way). …
How do you calculate flue gas flow rate?
Most power plants calculate flue gas flow rate from the net energy consumption derived from the fuel flow multiplied by the Net Calorific Value (NCV). Alternatively, the power or heat output is divided by the electrical or thermal efficiency, as appropriate, in order to determine the net energy consumption.
What is Draught in chimney?
Draught Draught is defined as “the pressure difference (between absolute gas pressure at any point in a gas flow passage and the atmospheric air outside the boiler) required to maintain flow of air and exhaust gases through the boiler setting.”
How to calculate pressure difference in a chimney?
The pressure difference or chimney draft can be expressed as: dp ch = h (ρ o – ρ i) a g (1) where. dp ch = pressure draft in the chimney (Pa) h = height of chimney (m) ρ o = ambient outside density of air (kg/m 3) ρ i = chimney inside density of air (kg/m 3)
What should the Efflux Velocity of a chimney be?
Maximum ground level concentrations occur at about 10 to 15 times the effective chimneys’ height distance down wind. For large power station chimneys in the UK, the design efflux velocity should not be less than 15 m/s at maximum continuous rating.
Which is the correct formula for chimney draft?
Chimney Draft. The pressure difference or chimney draft can be expressed as: dpch = h (ρo – ρi) ag (1) where. dpch = pressure draft in the chimney (Pa) h = height of chimney (m) ρo = ambient outside density of air (kg/m3)
How does the capacity of a chimney depend on?
The capacity of a chimney depends on the potential chimney draft – the pressure difference created by the inside and outside air temperature difference and chimney height – and the chimney area. The pressure difference in the chimney pulls air and fuel gas from the boiler or fireplace through the chimney and out of the building. Chimney Draft.