MICROCOMPUTERS AND APPROPRIATE SOFTWARE PERMIT ACCURATE PRESSURE DISTRIBUTION FROM LOW COST TRANSDUCERS.

Experimental flow research and process regulation need the pressure to be known in a considerable number of points of the flow field. Basically there are three possible ways of measuring a pressure cost price Firstly a pressure probe, connected to a transducer, may be mounted on a carriage in such a way that the probe head follows a specified path. For some applications the wall static pressure distribution is of a particular interest. In such cases it is common practice to scan the pressure holes by connecting them successively to a single transducer. The investment for a scanner and a single transducer may be considerably lower than for the third alternative, wherein each pressure tap is equipped with its individual transducer. Due to the uncertainty about the behaviour of a pneumatic scanner in such unfavourable conditions, the third possibility is sometimes advisable. Obviously, when the number of pressure taps is high, the transducer cost price becomes of the highest importance. Other consequences of this solution are a time consuming calibration procedure and cumbersome interfacing problems, on both soft and hardware levels, when data are to be transfered to a recording device. This technique is also very useful for investigation of instationary phenomena. This paper discusses various application considerations in terms of transfer functions, calibration of reference transducer, software descriptions, and related subjects. 2 refs.