DESCRIPTION

Technical Description

When laying pipes it is essential that they are adapted to the circumstances of their environment, which means the pipes will necessarily include deflections in the form of bends. Changing the direction of flow in a pipe changes the pressure conditions. The pressure curve during a change in the flow direction is investigated using the example of a 90° pipe bend.

The experimental unit HM 225.05, when used in the aerodynamics trainer HM 225, allows the measurement of the static pressure at 28 pressure measuring points along the pipe bend. The transparent pipe bend has a constant rectangular cross-section with 10 pressure measuring points each on the top and bottom. Four pressure measuring points are located in the region of the curvature on both sides. The pressure measuring points are connected to the tube manometers in HM 225 via the hoses supplied. The static pressures can be read on the tube manometers. 

To illustrate the pressure distribution, the static pressure at a measuring point is related to the maximum pressure. The graphical representation of the pressure curve shows a low pressure along the inner radius and an overpressure along the outer radius. Secondary flows occur to compensate for the pressure difference.

As a result of friction at boundary layers there are separation vortices at the inner radius.

The experimental unit is attached to the HM 225 trainer, simply and precisely with quick release fasteners.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- investigation of the pressure curve at a 90° pipe bend
- determination of the static pressure at 28 pressure measuring points
- representation of the pressure distribution