Definition of swirl number of burner

The primary air of a kiln main burner is normally split into "axial" and "swirl" air, with each being a percentage of the total and their sum equalling 100%. The flame shape is adjusted by varying the proportions of axial and swirl air. However, there is no formula (that I know of) which relates the shape to the %swirl air. The importance is to record the percentages to establish the base line for optimum kiln operation.

The swirl air and the setting of it is utmost important to the sintering process. This setting substantially influences the flame shape and the flame shape itself mainly influences the heat transfer into the clinker bed. And this influences the sintering process thus the free lime and cement quality extensively. So the key to optimising the sintering process lies in optimising heat transfer into the clinker.

It is not enough to once find the best setting or relation! Its a burner-life-long job to optimize this. This is one reason why burner producers like Pillard /Unitherm / Greco are offering full automation for the swirl air setting.

However, the flame shape and flame temperature are determined by several varying influences but one of the utmost important is the swirl air. This arises the questions: "What is the optimum flame shape?" and "How can I measure a flame shape?"

The answers to these questions are given in my article in the June issue of WorldCement: "Enhancing Production Efficiency", if you don't have the chance to read it, just send me an e-mail (alexander.hanf@powitec.de) and I will send it to you

A very efficient tool to measure the flame shape and to see what influences the swirl air has to your process ist delivered by Powitec and described in that article. Furthermore the tool to life-long automated optimization is described.

Regards

Alexander Hanf