Hot-wire and PIV characterisation of a novel small-scale turbulent channel flow facility developed to study premixed expanding flames

ABSTRACT

We demonstrate a small-scale channel flow facility with passive and active turbulence generators for the study of spherically expanding turbulent flames. Traditionally, this canonical flame type is investigated in stagnant cylindrical combustion chambers with imposed turbulence. Incorporating a convective flow allows for a wider variety of flowfields and turbulence conditions to be studied. We compare the turbulence properties of our novel facility with cylindrical chambers and large-scale wind tunnels, discussing the design and validation strategy along with quantifiable turbulence properties. Measurements are made utilising hot-wire anemometry (HWA) and particle image velocimetry (PIV). The turbulent properties are analysed for a range of Reynolds numbers ( 130–480, computed from streamwise RMS velocities and transverse Taylor microscales). Comparing PIV results with HWA, emphasise is put on the achievement of sensible estimates for small-scale quantities relevant to mixing. The facility is demonstrated to have the requisite capability to study expanding premixed flame kernels under the influence of intense turbulence in a windtunnel-like configuration with no precedence in the literature. Based on several criteria, it is shown that homogeneous isotropic turbulence can be achieved in much smaller dimensions than expected from classic windtunnel studies.

KEYWORDS:

• Hot-wire anemometry
• PIV
• isotropic turbulence
• active grid
• channel turbulence

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Corrigendum

Acknowledgments

The first author would like to thank Prof. Laurent Mydlarski at McGill University for providing clarifications and Professor Takashi Ishihara at Nagoya University for providing the data reproduced in Figure 9.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Air Force Office of Scientific Research under basic research grant [grant number FA9550-15-1-0512].