The University of Southampton
University of Southampton Institutional Repository

Effect of expansion chamber geometry on atomization and spray dispersion characters of a flashing mixture containing inerts. Part I. Numerical predictions and dual laser measurements

Effect of expansion chamber geometry on atomization and spray dispersion characters of a flashing mixture containing inerts. Part I. Numerical predictions and dual laser measurements
Effect of expansion chamber geometry on atomization and spray dispersion characters of a flashing mixture containing inerts. Part I. Numerical predictions and dual laser measurements
A cigarette alternative is designed to deliver a dose of medicinal nicotine within a timeframe comparable to that of a cigarette, and gives much of what smokers expect from a cigarette without the risks of smoking tobacco. The design concept is the same as a pressurized metered dose inhaler (pMDI), but is a breath actuated device (Oxette®). This work predicts the residual mass median diameter (MMD) of the spray issuing from early stage Oxette® prototypes by using an evaporation model of multi-component liquid droplets with the help of a numerical multi-component two-phase actuation model (developed by the authors) to quantify the sprays. Two different formulations with 95% and 98% mass fraction of HFA 134a, and two prototypes of cigarette alternatives with different expansion chamber volumes have been analyzed by the numerical model and compared with laser based measurements. The later designed device provides a larger expansion chamber volume to enhance the propellant evaporation, recirculation, bubble generation and growth inside the chamber, and it makes a significant improvement to produce finer sprays than the earlier design. The mass fraction of the formulation does not affect significantly on the initial MMD of the droplets near the discharge orifice. However, it influences the residual MMD at x = 100 mm from the discharge orifice, where the ratio of the predicted residual MMDs of the droplets generated by the formulations with 98% and 95% of HFA 134a is 0.73. Although the formulation with 98% of HFA 134a can generate smaller droplets, the formulation with 95% of HFA 134a produces more steady puffs with relatively low mass flow rate
0378-5173
23-31
Ju, Dehao
152e0f9a-b36c-4acf-9a21-6be7dd0515f9
Shrimpton, John
9cf82d2e-2f00-4ddf-bd19-9aff443784af
Bowdrey, Moira
8ede6859-0e92-4fb0-8667-ba4ec5edda6a
Hearn, Alex
3f049947-40b7-4fa4-b6f1-28df4a68deb9
Ju, Dehao
152e0f9a-b36c-4acf-9a21-6be7dd0515f9
Shrimpton, John
9cf82d2e-2f00-4ddf-bd19-9aff443784af
Bowdrey, Moira
8ede6859-0e92-4fb0-8667-ba4ec5edda6a
Hearn, Alex
3f049947-40b7-4fa4-b6f1-28df4a68deb9

Ju, Dehao, Shrimpton, John, Bowdrey, Moira and Hearn, Alex (2012) Effect of expansion chamber geometry on atomization and spray dispersion characters of a flashing mixture containing inerts. Part I. Numerical predictions and dual laser measurements International Journal of Pharmaceutics, 432, (1-2), pp. 23-31. (doi:10.1016/j.ijpharm.2012.04.065).

Record type: Article

Abstract

A cigarette alternative is designed to deliver a dose of medicinal nicotine within a timeframe comparable to that of a cigarette, and gives much of what smokers expect from a cigarette without the risks of smoking tobacco. The design concept is the same as a pressurized metered dose inhaler (pMDI), but is a breath actuated device (Oxette®). This work predicts the residual mass median diameter (MMD) of the spray issuing from early stage Oxette® prototypes by using an evaporation model of multi-component liquid droplets with the help of a numerical multi-component two-phase actuation model (developed by the authors) to quantify the sprays. Two different formulations with 95% and 98% mass fraction of HFA 134a, and two prototypes of cigarette alternatives with different expansion chamber volumes have been analyzed by the numerical model and compared with laser based measurements. The later designed device provides a larger expansion chamber volume to enhance the propellant evaporation, recirculation, bubble generation and growth inside the chamber, and it makes a significant improvement to produce finer sprays than the earlier design. The mass fraction of the formulation does not affect significantly on the initial MMD of the droplets near the discharge orifice. However, it influences the residual MMD at x = 100 mm from the discharge orifice, where the ratio of the predicted residual MMDs of the droplets generated by the formulations with 98% and 95% of HFA 134a is 0.73. Although the formulation with 98% of HFA 134a can generate smaller droplets, the formulation with 95% of HFA 134a produces more steady puffs with relatively low mass flow rate

Full text not available from this repository.

More information

Published date: 2012
Organisations: Faculty of Engineering and the Environment

Identifiers

Local EPrints ID: 349246
URI: http://eprints.soton.ac.uk/id/eprint/349246
ISSN: 0378-5173
PURE UUID: defdca61-0221-4131-a75c-98aebf4c08c4

Catalogue record

Date deposited: 27 Feb 2013 09:48
Last modified: 18 Jul 2017 04:43

Export record

Altmetrics

Contributors

Author: Dehao Ju
Author: John Shrimpton
Author: Moira Bowdrey
Author: Alex Hearn

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×