| Author: | Uy, Chun Kit |
| Title: | Theoretical and numerical investigation on vibrational nonequilibrium effect in detonation |
| Advisors: | Wen, Chih-yung (ME) |
| Degree: | Ph.D. |
| Year: | 2020 |
| Subject: | Gas dynamics -- Mathematical models Relaxation (Gas dynamics) Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | xii, 102 pages : illustrations |
| Language: | English |
| Abstract: | This thesis attempts to elucidate the effect of vibrational nonequilibrium in detonation by theoretically modelling. A simplified vibrational-chemical coupling mechanism is constructed by correlating single-step/two-step Arrhenius equations (denoting chemical reaction) and the Landau-Teller model (denoting vibrational relaxation) with Park's two-temperature model. Two issues are demonstrated based on these coupling kinetics, which include 1) the extension of the ZND detonation model to predict half-reaction length when detonation is under significant vibrational nonequilibrium and 2) the stability behaviour of detonation under significant vibrational nonequilibrium. A time ratio denoting the ratio of chemical reaction time scale and the vibrational relaxation time scale is utilized throughout this study and it represents the different state of vibrational nonequilibrium. In the first half of the thesis, it is concluded that the elongation of half reaction length at the state of nonequilibrium is observed due to the reduction of overall chemical reaction rate, whereas in the second half of the thesis, it is shown that the detonation is stabilized at vibrational nonequilibrium state through a normal mode linear stability analysis. The results obtained in the analytical approach are compared with that using a numerical approach by CE/SE scheme, and these findings are well verified. The theoretical derivation in the detonation model indicates that vibrational nonequilibrium and thus the vibrational-chemical coupling mechanism plays an important role in gaseous detonation physics and should be examined further in future detonation simulations. |
| Rights: | All rights reserved |
| Access: | open access |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/11079