DESCRIPTION

Technical Description

The vapour content x is a dimensionless ratio between 0 and 1. It is defined by the ratio of mass of vapour and total mass. The total mass is calculated from the sum of fluid mass and vapour mass. If the vapour content is x=0, the evaporation medium is completely liquid, x=1 means dry saturated vapour, a value in between means wet steam with a variable liquid content.  Separating and throttling calorimeters are used to determine the vapour content. In practice, devices to determine the vapour content are used in steam power plants, downstream of steam turbines or at steam boilers upstream of the superheater.

The ET 805.50 trainer uses a two-stage method to determine the vapour content. A separating calorimeter with cyclone water separator is used to determine vapour contents with a high liquid content (0,5

A downstream throttling calorimeter is used to determine vapour contents between x=0,95 and x=1. The wet steam is depressurised in this process. The remaining vapour part is depressurised and then liquefied in a water-cooled condenser and also collected in a measuring beaker. The two quantities can be used to determine vapour mass and total mass to calculate the vapour content. 

Sensors measure the pressure and temperature before and after depressurisation. The measuring results can be used to determine the vapour content with the h-s diagram.  

The water vapour has to be generated externally, e.g. with the electrical steam generator WL 315.02. To determine the vapour content of the steam power plants ET 805, ET 830, ET 850 or ET 833, ET 805.50 is recommended.

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

Learning Objectives / Experiments

- determining the vapour content using
  * a separating calorimeter with cyclone water separator
  * a throttling calorimeter with vapour depressurisation
- using an h-s diagram