Long-test-time Experiments

Traditional shock-tube test times (<10 ms) are inadequate for certain classes of experiments, particularly those targeting the negative temperature coefficient (NTC) ignition regime of large hydrocarbons.

In the Hanson Research Group, we apply multiple techniques to extend these test times including installing driver section extensions, using driver-section inserts, and driver gas tailoring. These extended test times are essential to experimentally measure ignition delay times, rate constants and non-equilibrium phenomenon at practical conditions.

Through the combination of these strategies, one of the Hanson Research Group’s shock tubes (AST) has demonstrated the longest-ever constant-pressure shock-tube test times (>100 ms under certain conditions). With these techniques, our group studies next-generation high-efficiency engines and turbomachinery of practical importance, such as supercritical CO₂ turbines.

time versus pressure during a long-test-time shock tube experiment — Constant-pressure test times in AST with varied driver-gas tailoring and driver section extensions installed [1]

To learn more, check out some of our publications:

[1] M. F. Campbell, T. Parise, A. M. Tulgestke, R. M. Spearrin, D. F. Davidson, and R. K. Hanson, "Strategies for obtaining long constant-pressure test times in shock tubes," Shock Waves, Vol. 25 (2015) pp. 651–665. DOI: 10.1007/s00193-015-0596-x

[2] Z. Hong, G.A. Pang, S.S. Vasu, D.F. Davidson, R.K. Hanson, "The use of driver inserts to reduce non-ideal pressure variations behind reflected shock waves," Shock Waves, Vol. 19, 2009, pp. 113–123. DOI: 10.1007/s00193-009-0205-y