1915] Gaseous Explosions 269 





WEEKLY EVENING MEETINGK 





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Friday, January 29, 1915. \-^- \ '"^^ -.^^^ 



Edward Pollock, F.R.C.S., Tice-President^;, 4t . >^t'y ^ 

 in the Chair. "^--^* — ^^ * j 



DuGALD Clerk, D.Sc. F.R.S. M.Inst.C.E. M.R.I. j 



! 



Gaseous Explosions. I 



The investigation of gaseous explosions is of interest to Chemists,. 

 Physicists, and Engineers. The Chemist studies the laws of com- 

 bination and dissociation ; the Physicist deals with modes and rates 

 of inflammation, variation of specific heat, maximum temperatures 

 attained, and laws of radiation and cooling ; while the Engineer con- 

 siders both chemical and physical effects as bearing on the practical 

 operation and thermo-dynamics of the internal combustion engine.. I 



He also interests himself in the analogous phenomena of inflammable 

 dust explosions as found in coal-mine and flour-mill accidents. 



The matters of interest are obviously numerous and complicated ; 

 and it is accordingly necessary to limit their consideration to a few 

 points. The points selected will be dealt with as they bear more 

 particularly on the engineering problems of the internal combustion 

 engine. 



In 1907 the British Association, at their Leicester Meeting, 

 appointed a Committee of Investigation. This Committee has been 

 at work ever since, and much hght has been thrown by the experi- 

 ments of its members upon the facts connected with gaseous explo- 

 sions as occurring in closed vessels and within engine cylinders having 

 moving pistons. It is now proposed to describe some of the work of ] 



the Committee, dealing first with the phenomena of rising tempera- 

 ture, and second with that of cooling after explosion. 



When a mixture of coal gas and air is ignited within a strong 

 closed vessel, it is found that the pressure rises rapidly, attains a 

 maximum, and falls relatively slowly. To this rapid pressure rise is 

 due the term gaseous explosion. 



Such explosions are obtained ivith mixtures of all inflammable 

 gases or vapours with air or oxygen, and very similar phenomena , 



occur with like mixtures of inflammable dust. 



The rise and fall of pressure is studied by means of sensitive 

 indicator devices, which produce tracings on a rotating drum. I 



Vol. XXL (No. 109) T ! 



