Combustion and microexplosion of collision-merged methanol/alkane droplets

C. H. Wang; S. Y. Fu; L. J. Kung; C. K. Law

doi:10.1016/j.proci.2004.08.111

Combustion and microexplosion of collision-merged methanol/alkane droplets

C. H. Wang, S. Y. Fu, L. J. Kung, C. K. Law

Princeton University

Research output: Contribution to journal › Conference article › peer-review

24 Scopus citations

Abstract

The combustion characteristics of freely falling droplets, individually generated by the merging of colliding methanol and alkane droplets, were studied and compared with those for pure methanol and alkanes. An air bubble was trapped at the colliding interfaces where they were adhered, with the trapping favored for head-on or near head-on collision orientations. The trapped air bubble ostensibly induced heterogeneous nucleation of the methanol, being facilitated by the relatively low limit of superheat of methanol. Consequently, the droplet exploded almost immediately upon ignition, leading to an extremely short overall lifetime. For collision orientations that were more off-centered, bubble trapping and heterogeneous nucleation were not favored. However, delayed, albeit strong, microexplosion occurred through homogeneous nucleation of methanol at the contacting interface. Microexplosion was facilitated for high-boiling-point alkanes such as hexadecane and tetradecane. The co-vaporization of methanol and alkane from their respective hemispherical segments constituting the adhered droplet also led to flame colors that were more bluish than yellowish, indicating the reduction of soot from alkane burning in the presence of methanol vapor. In light of the difficulty of forming stable methanol/oil emulsions, the potential of separate injection of oil and methanol in opposed jet arrangement, in direct-injection engines to facilitate collision, was suggested. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).

Original language	American English
Pages (from-to)	1965-1972
Number of pages	8
Journal	Proceedings of the Combustion Institute
Volume	30 II
Issue number	2
DOIs	https://doi.org/10.1016/j.proci.2004.08.111
State	Published - 2005
Event	30th International Symposium on Combustion - Chicago, IL, United States Duration: Jul 25 2004 → Jul 30 2004

ASJC Scopus subject areas

General Chemical Engineering
Mechanical Engineering
Physical and Theoretical Chemistry

Keywords

Droplet collision
Droplet combustion
Methanol combustion

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10.1016/j.proci.2004.08.111

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title = "Combustion and microexplosion of collision-merged methanol/alkane droplets",

abstract = "The combustion characteristics of freely falling droplets, individually generated by the merging of colliding methanol and alkane droplets, were studied and compared with those for pure methanol and alkanes. An air bubble was trapped at the colliding interfaces where they were adhered, with the trapping favored for head-on or near head-on collision orientations. The trapped air bubble ostensibly induced heterogeneous nucleation of the methanol, being facilitated by the relatively low limit of superheat of methanol. Consequently, the droplet exploded almost immediately upon ignition, leading to an extremely short overall lifetime. For collision orientations that were more off-centered, bubble trapping and heterogeneous nucleation were not favored. However, delayed, albeit strong, microexplosion occurred through homogeneous nucleation of methanol at the contacting interface. Microexplosion was facilitated for high-boiling-point alkanes such as hexadecane and tetradecane. The co-vaporization of methanol and alkane from their respective hemispherical segments constituting the adhered droplet also led to flame colors that were more bluish than yellowish, indicating the reduction of soot from alkane burning in the presence of methanol vapor. In light of the difficulty of forming stable methanol/oil emulsions, the potential of separate injection of oil and methanol in opposed jet arrangement, in direct-injection engines to facilitate collision, was suggested. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).",

keywords = "Droplet collision, Droplet combustion, Methanol combustion",

author = "Wang, {C. H.} and Fu, {S. Y.} and Kung, {L. J.} and Law, {C. K.}",

note = "Funding Information: The work at the National Taiwan University was supported by the National Science Foundation of Taiwan, Republic of China, and that at Princeton University was supported by the US Air Force Office of Scientific Research under the technical monitoring of Dr. Mitat Birkan.; 30th International Symposium on Combustion ; Conference date: 25-07-2004 Through 30-07-2004",

year = "2005",

doi = "10.1016/j.proci.2004.08.111",

language = "American English",

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TY - JOUR

T1 - Combustion and microexplosion of collision-merged methanol/alkane droplets

AU - Wang, C. H.

AU - Fu, S. Y.

AU - Kung, L. J.

AU - Law, C. K.

N1 - Funding Information: The work at the National Taiwan University was supported by the National Science Foundation of Taiwan, Republic of China, and that at Princeton University was supported by the US Air Force Office of Scientific Research under the technical monitoring of Dr. Mitat Birkan.

PY - 2005

Y1 - 2005

N2 - The combustion characteristics of freely falling droplets, individually generated by the merging of colliding methanol and alkane droplets, were studied and compared with those for pure methanol and alkanes. An air bubble was trapped at the colliding interfaces where they were adhered, with the trapping favored for head-on or near head-on collision orientations. The trapped air bubble ostensibly induced heterogeneous nucleation of the methanol, being facilitated by the relatively low limit of superheat of methanol. Consequently, the droplet exploded almost immediately upon ignition, leading to an extremely short overall lifetime. For collision orientations that were more off-centered, bubble trapping and heterogeneous nucleation were not favored. However, delayed, albeit strong, microexplosion occurred through homogeneous nucleation of methanol at the contacting interface. Microexplosion was facilitated for high-boiling-point alkanes such as hexadecane and tetradecane. The co-vaporization of methanol and alkane from their respective hemispherical segments constituting the adhered droplet also led to flame colors that were more bluish than yellowish, indicating the reduction of soot from alkane burning in the presence of methanol vapor. In light of the difficulty of forming stable methanol/oil emulsions, the potential of separate injection of oil and methanol in opposed jet arrangement, in direct-injection engines to facilitate collision, was suggested. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).

AB - The combustion characteristics of freely falling droplets, individually generated by the merging of colliding methanol and alkane droplets, were studied and compared with those for pure methanol and alkanes. An air bubble was trapped at the colliding interfaces where they were adhered, with the trapping favored for head-on or near head-on collision orientations. The trapped air bubble ostensibly induced heterogeneous nucleation of the methanol, being facilitated by the relatively low limit of superheat of methanol. Consequently, the droplet exploded almost immediately upon ignition, leading to an extremely short overall lifetime. For collision orientations that were more off-centered, bubble trapping and heterogeneous nucleation were not favored. However, delayed, albeit strong, microexplosion occurred through homogeneous nucleation of methanol at the contacting interface. Microexplosion was facilitated for high-boiling-point alkanes such as hexadecane and tetradecane. The co-vaporization of methanol and alkane from their respective hemispherical segments constituting the adhered droplet also led to flame colors that were more bluish than yellowish, indicating the reduction of soot from alkane burning in the presence of methanol vapor. In light of the difficulty of forming stable methanol/oil emulsions, the potential of separate injection of oil and methanol in opposed jet arrangement, in direct-injection engines to facilitate collision, was suggested. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).

KW - Droplet collision

KW - Droplet combustion

KW - Methanol combustion

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DO - 10.1016/j.proci.2004.08.111

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SN - 1540-7489

VL - 30 II

SP - 1965

EP - 1972

JO - Proceedings of the Combustion Institute

JF - Proceedings of the Combustion Institute

IS - 2

T2 - 30th International Symposium on Combustion

Y2 - 25 July 2004 through 30 July 2004

ER -

Combustion and microexplosion of collision-merged methanol/alkane droplets

Abstract

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Keywords

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