Thermal Efficiency of Oxy-Acetylene Flame (Report 1)

Abstract

The thermal efficiency of oxy-acetylene flame have not been determined by the researchers of gas welding fields. It is necessary, however, to the fundamental study of oxy-acetylene welding and allied processes.
Authers have measured the value experimentary with simple apparatus. The skelton diagram of heating apparatus was shown in Fig. 1. The heated specimen of mild steel plate 100 x 100 mm (3.2, 4.6, 6.5 and 10.3 mm in thickness) was inserted into the calorimeter as shown in Fig. 2. The thermal efficiency was defined as follow ;
thermal effciency=received heat quantity of specimen/total heat combustion of oxy-acetylene flame ×100%
In this experiment, if the plate thickness and tip distance (L) were varied, relations between the thermal efficiency and mixed ratio O₂/C₂H₂ were shown as Fig. 5-8. Effects of heating time and tipangles to the thermal efficiency were shown in Fig. 13 and Fig. 14.
The test results can be described as follows ;
1) The thermal efficiency of oxy-acetylene flame is 45-75%. But in case the plate surface is melted, it is about 45-55%.
2) The thermal efficiency is gradually increased according to the decrease of the tip distance.
3)The thermal efficiency is increased according to the increase of the mixed ratio.
4) In case the plate surface is. not melted, the thermal efficiency is slightly increased according to the increase of plate thickness even if the same heating time is used. And in case the plate of same thickness are used, the thermal efficiency is decreased according to the increase of heating time.
5) In case the heating is -done until the plate surface, just below the white cone only, is melted, the thermal efficiency is increased according to decreases of plate thickness and mixed ratio.
6) The thermal efficiency is increased according to the increase of the tip angle.