Thrust at Pipe Bend



Calculation Reference
Thrust at Pipe Bend
Pipe Engineering
Stress in Pipes

When fluid flows through a pipe bend, it generates a force known as thrust due to the change in momentum of the fluid. The thrust force in the pipe bend can result in stresses on the pipe and its supports. Calculating the thrust force and the resulting stresses is an essential part of pipe engineering to ensure proper design and support.

To calculate the thrust force at a pipe bend, you can use the following formula:

F = ρ * Q * V * sin(θ)


F = Thrust force (Newtons, N) ρ = Fluid density (kg/m³) Q = Flow rate (m³/s) V = Fluid velocity (m/s) θ = Bend angle (in radians)

To convert the bend angle from degrees to radians, use the following formula:

θ (radians) = θ (degrees) * π / 180

After calculating the thrust force, you can calculate the resulting stresses in the pipe bend. The most common stresses that need to be considered are:

  1. Longitudinal stress (σL) due to the thrust force in the pipe bend: σL = F / (2 * t * R)

Where: σL = Longitudinal stress (Pascals, Pa) F = Thrust force (Newtons, N) t = Pipe wall thickness (meters, m) R = Mean radius of the pipe bend (meters, m)

  1. Hoop stress (σH) due to internal pressure in the pipe: σH = (P * D) / (2 * t)

Where: σH = Hoop stress (Pascals, Pa) P = Internal pressure (Pascals, Pa) D = Pipe diameter (meters, m) t = Pipe wall thickness (meters, m)

It's crucial to ensure that the calculated stresses do not exceed the allowable stress limits for the pipe material. You should also consider other factors, such as temperature, corrosion, and fatigue, when designing pipe systems and their supports.

In summary, to assess the thrust force at a pipe bend and the resulting stresses, you need to determine the fluid density, flow rate, fluid velocity, bend angle, pipe wall thickness, and mean radius of the bend. After calculating the thrust force, you can evaluate the longitudinal and hoop stresses in the pipe bend to ensure the pipe's proper design and support.

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11 Dec 2015
Last Modified
25 Apr 2023
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File Author:
Alex Ganschow

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Comments: 1
JohnDoyle[Admin] 8 years ago
Thanks for your début calculation I have awarded a free three month XLC Pro subscription by way of thanks.