OCR Text |
Show The coefficient was developed to use measurable properties for injection. The conditions for the testing were chosen to be similar to actual, and since only comparative testing was done, more convenient conditions were chosen at which the properties were to be measured. Conditions inside the combustion chamber were assumed to be the same for all fuels; therefore, tests were conducted for injection into ambient air. The combustion chamber shape was of prime importance, thus a circular cylinder was used for the tests. The specific equipment used to make the measurements were (Figure 2.); . a 7.625 in diameter plexiglass cylinder and stand, . an injector nozzle mounted inside the cylinder, . an injector pressure test machine, . yellow heavy bond construction paper. The injector pressure test machine was an adjustable pressure chamber equipped with a pressure gauge to record the fuel pressure supplied for injection. This pressure was the INOP for the test injector. The test performed consisted of lining the cylinder with construction paper, loading the injector to its nozzle opening pressure, and supplying a single discharge of fuel. This discharge was visible by discoloration on the construction paper. The areas and positions were recorded as quickly as possible to prevent errors due to different spreading rates. The positions of the spots with respect to the holes in the injector nozzle were recorded. From this test the spray angle, the length of spray, and spray area were determined. The area of the spots was measured using a K&E planimeter. The total area was divided by the number of discharge holes to obtain the average spray area A . The spray length, L , was the length from the *The color yellow was chosen for its high resolution of the discoloration of the fuel spots and the outline of the spot area. -21- |