Hydraulic diameter is mainly
used for calculations involving turbulent flow
. Secondary flows can be observed in non-circular ducts as a result of turbulent shear stress in the turbulent flow. Hydraulic diameter is also used in calculation of heat transfer in internal-flow problems.
What is the difference between hydraulic diameter and equivalent diameter?
Note! The
hydraulic diameter
is not the same as the
equivalent diameter
. The
equivalent diameter
is the
diameter
of a circular duct or pipe that gives the same pressure loss as a rectangular duct or pipe.
What is the significance of hydraulic diameter in fluid flow system?
The hydraulic diameter (aka hydraulic mean diameter) is used for a fluid flowing in a pipe, duct or other conduit of any shape. This
uses the perimeter and the area of the conduit to provide the diameter of a pipe which has proportions such that conservation of momentum is maintained
.
What is hydraulic diameter used in place of diameter for non-circular ducts equal to where a area of flow and M wetted perimeter?
Note! – the hydraulic diameter is not the same as the geometrical equivalent diameter of non-circular ducts or pipes.
dh = 4 A / p (1)
where dh = hydraulic diameter (m, ft) A = area section of the duct or pipe (m2, ft2) p = “wetted” perimeter of the duct or pipe (m, ft) Note!
How is hydraulic diameter derived?
The hydraulic diameter is calculated as
4 times the cross-sectional flow area divided by the wetted perimeter of the conduit/pipe
. ) is often used for systems with free surface flows, such as water in open channels, streams or rivers.
How is the hydraulic diameter defined in an annulus tube?
The hydraulic diameter is
four times the flow area divided by the duct perimeter
.
What is the hydraulic mean depth?
The cross section of water flowing through a channel or pipe divided by the wetted perimeter of the conduit
. Synonym of: hydraulic radius.
What is the equivalent of a diameter?
The equivalent diameter is defined as
the diameter of a circle with an equal aggregate sectional area
, which is calculated by d = 2 Area / π .
What is equivalent diameter used for?
The equivalent diameter is
the diameter of a circular duct or pipe that for equal flow gives the same pressure loss or resistance as an equivalent rectangular duct or pipe
. A round shape results in lower pressure drops and less fan horsepower to move the air and, consequently, smaller equipment.
How many times do we calculate effective diameter hydraulic diameter for a double pipe heat exchanger?
4. How many times do we calculate effective diameter/hydraulic diameter for a double pipe heat exchanger? Explanation: We calculate the hydraulic diameter only for the outer annulus tube as its flow area is different than that of the inner tube. 5.
How do you calculate the Reynolds number of a flow in a duct using the hydraulic diameter?
Reynolds Number Formula for Pipe Flow
The hydraulic diameter is determined with:
“D
H
= 4A/P”
where “P” is the “wetted perimeter”, or the area that contacts the fluid flow.
What is the hydraulic radius of a pipe?
The hydraulic radius is a direct function of the shape of its conduit. For example, for circular cross-sections, such as sewers and pipe culverts, the hydraulic radius is not half the diameter, as the name implies. The hydraulic radius, in this case, is
one quarter the diameter of a full pipe
.
What is wetted perimeter of a pipe?
The wetted perimeter of the pipe is
the portion of the total pipe perimeter that is in contact with the flowing liquid
(for example, water).
What is hydraulic radius used for?
The hydraulic radius is one of the
properties of a channel that controls water discharge
. It also determines how much work the channel can do, for example, in moving sediment.
How do you find the hydraulic radius?
Rh is the
hydraulic radius = A/P.
P is the wetted perimeter of the cross-sectional area of flow in ft. *You may recall that uniform open channel flow (which is required for use of the Manning equation) occurs for a constant flow rate of water through a channel with constant slope, size and shape, and roughness.
What is cross section area?
The cross-sectional area is
the area of a two-dimensional shape that is obtained when a three-dimensional object – such as a cylinder
– is sliced perpendicular to some specified axis at a point. For example, the cross-section of a cylinder – when sliced parallel to its base – is a circle.
