Constrained Reaction Volume Experiments

Shock tube measurements are often used to refine and validate detailed kinetic models, which are in turn used by industry practitioners to develop advanced energy systems.

Data obtained from shock tube experiments are most useful when the experiments are well described by simple thermodynamic constraints, such as constant pressure or constant volume.

The constrained reaction volume (CRV) method was developed and optimized in our lab to enable shock tube experiments to be conducted under nearly ideal constant-pressure conditions. In the CRV method, a portion of the driven gas is replaced by a carefully selected, inert “buffer” gas by means of either staged gas filling [1] or a sliding gate valve (banner photo) [2]. By confining the reactive gas to a small fraction of the driven gas, remote ignition events and the effects of energy release are minimized.

Running experiments in this manner not only simplifies their simulation but also enables the study of non-dilute fuel-air mixtures required to unlock certain experimental domains (e.g., low-temperature ignition [4]) and ensures the utmost relevance to practical applications in energy systems.

Schematics showing the two strategies for realizing CRV experiments in a shock tube (adapted from [3])

To learn more, check out some of our publications:

[1] R. K. Hanson, G. A. Pang, S. Chakraborty, W. Ren, S. Wang, D. F. Davidson, “Constrained reaction volume approach for studying chemical kinetics behind reflected shock waves,” Combustion and Flame, Vol. 160:9 (2013), pp. 1550–1558. DOI: 10.1016/j.combustflame.2013.03.026

[2] M. F. Campbell, A. M. Tulgestke, D. F.Davidson, and R. K. Hanson, “A second-generation constrained reaction volume shock tube,” Review of Scientific Instruments, Vol. 85:5 (2014) pp. 055108. DOI: 10.1063/1.4875056

[3] A. J. Susa, D. F. Davidson, and R. K. Hanson, “Gravity-current-induced test gas stratification and its prevention in constrained reaction volume shock-tube experiments,” Shock Waves, Vol. 29:7 (2019), pp. 969–984. DOI: 10.1007/s00193-019-00894-3

[4] M. F. Campbell, S. Wang, C. S. Goldenstein, R. M. Spearrin, A. M. Tulgestke, L. T. Zaczek, D. F. Davidson, and R. K. Hanson, “Constrained reaction volume shock tube study of n-heptane oxidation: Ignition delay times and time-histories of multiple species and temperature,” Proceedings of the Combustion Institute, Vol. 35:1 (2015) pp. 231–239. DOI: 10.1016/j.proci.2014.05.001