A Pipe starts at 3cm(ID) and expands to 8cm(ID)
Water enters at the 3cm side at 7meters/second at 250 KPA.
What is the flow rate in m3/s through the pipe?> is it the same at both ends?
What is the velocity at the 8cm side?
What is the static pressure in the 8cm side?
I THINK the flow rate is the same in cubic meters/second at both ends just the pressure and velocity will change....
I THINK the velocity will be faster at the 3cm side than the 8cm side because the cross sectional area is greater...
I THINK the STATIC pressure would be the same on both ends of the pipe because it's STATIC....
I just cant figure it out mathematically!
HELP!!!!!
flow, velocity, and pressure question!
Re: flow, velocity, and pressure question!
For this kind of problems you can use flow rate and diameter calculator at: Diameter calculator
Here is the report that I have for your inputs:
CALCULATION REPORT
1. volumetric flow rate (q): q = 5 l/s
2. mass flow rate (w): w = 17999.988 kg/h
3. diameter (D): D = 3 cm
4. velocity (v): v = 7.0735536 m/s
5. cross section area (A): A = 706.8583 mm2
6. density (ρ): ρ = 1000 kg/m3
There I input 3 cm diameter and tried with different values of flow rate q until I have around 7 m/s velocity. Flow rate that I have is 5 l/s. To calculate velocity at 8 cm internal diameter I will keep the same flow rate and change the diameter to 8 cm and here are the results:
1. volumetric flow rate (q): q = 5 l/s
2. mass flow rate (w): w = 17999.988 kg/h
3. diameter (D): D = 8 cm
4. velocity (v): v = 0.9947185 m/s
5. cross section area (A): A = 5026.5483 mm2
6. density (ρ): ρ = 1000 kg/m
so instead of 7 m/s velocity, now we have about 1 m/s.
Mathematical (physical) equation for this you can find at Bernoulli theorem page
There is Bernoulli equation which shows how velocity and pressure are related between two points of one stream line. As diameter increase, velocity drops but pressure increase to keep total sum of one side of equation constant.
Static pressure is just term that means - it is the pressure without the influence of flow velocity. On the other hand dynamic pressure is the pressure that is created by fluid movement. Sum of static and total pressure is called total pressure and total pressure is constant in stream line like you can see at Static, dynamic and total pressure theory page.
Here is the report that I have for your inputs:
CALCULATION REPORT
1. volumetric flow rate (q): q = 5 l/s
2. mass flow rate (w): w = 17999.988 kg/h
3. diameter (D): D = 3 cm
4. velocity (v): v = 7.0735536 m/s
5. cross section area (A): A = 706.8583 mm2
6. density (ρ): ρ = 1000 kg/m3
There I input 3 cm diameter and tried with different values of flow rate q until I have around 7 m/s velocity. Flow rate that I have is 5 l/s. To calculate velocity at 8 cm internal diameter I will keep the same flow rate and change the diameter to 8 cm and here are the results:
1. volumetric flow rate (q): q = 5 l/s
2. mass flow rate (w): w = 17999.988 kg/h
3. diameter (D): D = 8 cm
4. velocity (v): v = 0.9947185 m/s
5. cross section area (A): A = 5026.5483 mm2
6. density (ρ): ρ = 1000 kg/m
so instead of 7 m/s velocity, now we have about 1 m/s.
Mathematical (physical) equation for this you can find at Bernoulli theorem page
There is Bernoulli equation which shows how velocity and pressure are related between two points of one stream line. As diameter increase, velocity drops but pressure increase to keep total sum of one side of equation constant.
Static pressure is just term that means - it is the pressure without the influence of flow velocity. On the other hand dynamic pressure is the pressure that is created by fluid movement. Sum of static and total pressure is called total pressure and total pressure is constant in stream line like you can see at Static, dynamic and total pressure theory page.
Pipe flow calculations - since 2000