What is hydraulic diameter and its impact on heat exchanger?
Table of Contents
- 1 What is hydraulic diameter and its impact on heat exchanger?
- 2 What is the significance of hydraulic diameter?
- 3 How is the hydraulic diameter defined in non-circular tubes?
- 4 What is the significance of Reynolds experiment?
- 5 Is hydraulic radius and hydraulic mean depth same?
- 6 What is the hydraulic diameter used in place of diameter for non-circular duct equal to?
What is hydraulic diameter and its impact on heat exchanger?
Hydraulic diameter – dh – is the “characteristic length” used to calculate the dimensionless Reynolds Number and Nu number. Therefore it is vital for evalution of different types of heat exchangers. In literature there are many different formulas which lead to different results (sometimes 5x difference).
What is the significance of hydraulic diameter?
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 radius in fluid mechanics?
Definition of hydraulic radius : the ratio of the cross-sectional area of a channel or pipe in which a fluid is flowing to the wetted perimeter of the conduit.
What is hydraulic diameter used in place of diameter for non-circular ducts equal to where a area of flow and M wetted perimeter?
– 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 the hydraulic diameter defined in non-circular tubes?
The hydraulic diameter, Dh, is a commonly used term when handling flow in non-circular tubes and channels. Using this term, one can calculate many things in the same way as for a round tube. In this equation A is the cross-sectional area, and P is the wetted perimeter of the cross-section.
What is the significance of Reynolds experiment?
Reynolds number helps us to determine whether the flow is laminar or turbulent. At high Reynolds numbers, the flow tends to be turbulent. Reynolds number is defined by the ratio of inertial forces to that of viscous forces.
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 . This is a classic method of an aggregate classification and used in many digital image processing programs.
What affects hydraulic radius?
These are channel slope, the roughness of the channel’s bed and banks and the cross-section channel shape. The higher the hydraulic radius the lower the amount of water in contact with the bed and banks which means there is less friction and water can move at a higher velocity.
Is hydraulic radius and hydraulic mean depth same?
Hydraulic Mean Depth and Hydraulic Radius. Thus, wetted perimeter times the hydraulic radius is equal to the area of irregular section flow as shown on figures 2-4a and 2-4c. Figure 2-4 — Definitions of hydraulic radius and hydraulic mean depth (area is the same for all three cases).