Book Description

The objective of this one-year program was to develop and demonstrate emission abatement technology sufficient to obtain a 50% overall reduction in gas turbine engine mass emissions (CO, CxHy, NOx and smoke) with no increase in any individual pollutant when tested over a typical Army light observation helicopter (LOH) duty cycle. The selected baseline was the Army T63-A-5A gas turbine engine combustor. Seventeen potential low-emission combustors, each incorporating one or more of the selected concepts, were tested to determine their emission performance. Experimental results indicated that several designs had the potential for meeting the program objectives. Two combustors selected for final experimental evaluation were the 'Prechamber' and 'Modified Conventional.' The low-emission feature in the 'Prechamber' combustor was premix/prevaporization. The 'Modified Conventional' combustor incorporated four low-emission features: airblast fuel atomization, delayed dilution, convection cooling, and variable geometry. Both of these combustors met the emission reduction objectives. Experimental results indicated that both of these liners can be developed to meet all other conventional T63 combustor requirements, i.e., light-off, temperature profile, durability, etc. The estimated development time for the 'Prechamber' is longer than for the 'Modified Conventional.' However, the 'Prechamber' combustor has better emission reduction potential when both combustors are designed as either fixed or variable geometry combustors.