Heat Release Rate Analysis of a DI Diesel Engine Using Diesel and Seawater Semi-Stable Emulsion 2002-01-2719

The lubricating oil and boiler feed water contamination is a regular feature in maritime operations. The author of this paper has stumbled upon the practical maritime problem of contamination of diesel fuel used for ship propulsion engine with the seawater. In the event of this contamination of diesel oil the author has made up his mind to evaluate the performance of a laboratory based diesel engine with various possible percentages of diesel emulsions with seawater closely keeping track of the engine performance.

The experimentation is conducted on a laboratory based DI 4-stroke Diesel engine (5 hp at 1500 rated RPM with Compression ratio 16.5) varying percentages of Diesel seawater emulsions. Appropriate engine data recorder and software is used to register the pressure variations with respect to crank-angle and heat release rate for various combinations of seawater and diesel emulsions. On scrutinizing the computed values of the graphic data recorded, the diesel emulsion with 10% seawater is found to be encouraging with regard to the pressure development, differential pressure and heat release rate. Specific graphs relating to the above data at the mentioned seawater emulsion are presented (Figs. 4, 5, 6) for comprehensive understanding of the combustion phenomena under various seawater contamination conditions of the diesel oil.

For the calculation of heat release rate and cumulative heat release rate based on the pressure and crank-angle diagram obtained from the recorder, the authors used the mathematical expressions formulated by A Ramesh et. al(12).

It is concluded that the aforesaid seawater-diesel oil emulsion is giving encouraging results at 3/4^th rated load of the engine. Improvement in the indicated horse power is observed to be 0. 3 KW (10% of the rated indicated output) over normal running of the engine with pure diesel.

This improvement in the power development is acclaimed to good diesel-air entrainment in the primary combustion stage. This entrainment is assumed to be taking place, because of the presence of the sea water which while burning splutters to create stirring in the combustion chamber. The P-θ signatures of both pure diesel and 10% diesel seawater emulsion confirm the improvement.

In marine diesel engines the purification regularity is to be maintained based on the contamination severity and for this an optimum of 10% seawater is recommended in the diesel propulsion engine from the observations made on the performance. Thus total purification, maintaining the zero seawater contamination may be avoided which reduces the purification cost and time.