What is equivalent diameter in heat exchanger?

Pressure drop calculation in heat exchangers is based on the Fanning–Darcy equation: (20.47) The equivalent diameter is given by deq = 4S/P, where S is the cross section and P the perimeter of the flow, L is the path length and ξ is a friction factor expressed as a function of Reynolds number and device geometry.

What is Shell equivalent diameter?

The equivalent diameter is calculated along (instead of across) the long axes of the shell and therefore is taken as four times the net flow area as layout on the tube sheet (for any pitch layout) divided by the wetted perimeter.

What is equivalent pipe diameter?

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.

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 equivalent diameter of a rectangle?

Equivalent diameter for rectangular and circular ducts – air flows between 100 – 50000 cfm. The equivalent diameter is the diameter of a circular duct or pipe that gives the same pressure loss as an equivalent rectangular duct or pipe.

What is baffle pitch?

The spacing between segmental baffles is called the baffle pitch. The baffle pitch and the baffle cut determine the cross flow velocity and hence the rate of heat transfer and the pressure drop. When the shell side heat transfer is sensible heating or cooling with no phase change, the baffle cut should be horizontal.

How would you determine the equivalent size of a compound pipe?

Equivalent pipe : The pipe of uniform diameter having loss of head and discharge equal to the loss of head and discharge of a compound pipe, consisting of several pipe of different length and diameters. Now, Let L1 = Length of pipe 1 and d1 = dia. L2 = Length of pipe 2 and d2 = dia. L3 Length of pipe 3 and d3 = dia.

How do you find a diameter?

The formula to find the diameter states the relationship between the diameter and the radius. The diameter is made up of two segments that are each a radius. Therefore, the formula is: Diameter = 2 * the measurement of the radius. You can abbreviate this formula as d=2r.

How do you calculate hydraulic diameter?

The hydraulic diameter is calculated as 4 times the flow area divided by the wetted perimeter of the conduit.

Why do we use hydraulic diameter?

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 equivalent diameter in a heat exchanger?

The equivalent diameter is 4 times the flow area over the wetted perimeter. If you work this out with a simple circular tube then the equivalent diameter is the diameter of the tube as you would expect it to be. This formula is useful for getting the Reynolds number for flow in an annulus of a double pipe HX for example.

How are heat transfer coefficients determined in concentric annuli?

concentric annuli, as cross section, the diameter ratio of the annular space plays an important role. The purpose of this investigation was to find a correlation that will accurately predict heat transfer coefficients at the inner wall of smooth concentric annuli for the flow of water. Experiments were

Why is annulus used in concentric tube heat exchanger?

The preference is to pass the hot fluid through the inner tube to reduce heat losses, while the annulus is reserved for the high viscosity stream to limit the pressure drop.

Which is the equivalent diameter of a circular tube?

Not sure that this is what the question seeks but here goes… The equivalent diameter is 4 times the flow area over the wetted perimeter. If you work this out with a simple circular tube then the equivalent diameter is the diameter of the tube as you would expect it to be.