Computer-based data acquisition of heat transfer in short-duration flow over a backward-facing step
Abstract
A data-acquisition system based on a LSI-11/2 microcomputer and a VAX-11/750 minicomputer has been developed for use with a 11 m long Ludwieg Tube Wind Tunnel. Signals from quartz pressure transducers, thin platinum film heat flux transducers and hot-wire anemometer are conditioned, recorded and processed using the LSI. The VAX is utilized to process data and display results. Use of the system allows one to reduce total processing time from one day (working manually) to 15 minutes. There is also an improvement in accuracy. With this system, wall heat fluxes for short-duration (20 ms) flow over a backward step are obtained. Two methods were used to treat data: (1) a Fourier Transform method; and (2) a least square method based on Duhamel's integral. The measured peak dimensionless heat transfer coefficient is 1.2, a value the same as that in the literature.
- Publication:
-
National Heat Transfer Conference
- Pub Date:
- August 1984
- Bibcode:
- 1984nht..conf.....T
- Keywords:
-
- Backward Facing Steps;
- Computer Techniques;
- Data Acquisition;
- Heat Transfer;
- Wind Tunnel Apparatus;
- Digital Filters;
- Flux Quantization;
- Heat Flux;
- Microcomputers;
- Minicomputers;
- Wall Flow;
- Fluid Mechanics and Heat Transfer