1 - Alaska Energy Data Inventory

The air chamber revisions include the addition of pressure head in theair chamber. Pressures, temperatures, and volumes are calculated using thepolytropic expressions:andWhere:P l= Initial pressure (abs) in air chamber in ft of water.P 2= Final pressure (abs) in air chamber in ft of water.V l= Initial volume in air chamber in ft 3 •V 2= Final volume in air chamber in ft 3 •Tl = Initial temperature in air chamber in degrees Rankine.T2 = Final temperature in air chamber in degrees Rankine.N = Polytropic gas constant (1.4).The exponent N has been set equal to 1.4 implying adiabatic behavior(no heat loss). Dr. Chaudhry, in Exhibit Bl at the end of this Appendixdiscusses this assumption and shows it to be suitable. The "MSURGE"program has been further expanded to inc 1 ude automat i c plott i ng of watersurface elevation, air pressure, hydraulic gradient at the tee, and turbineoutput vs. t"ime.G. Final Design - The Svee equation is a useful tool in locatingapproximate air volumes for incipient instability and in demonstrating howrequired air volumes will change with variations in certain variables(power tunnel diameter, turbine efficiency gradient, net head, tunnellength, etc.). The "MSURGfII program however, was used for final designcomputations -,for two major reasons: 1) it yielded somewhat higher (andthus more conservative) required air volumes, and 2) Dr. ChaudhryrecolTll1ended the use of IIMSURGE" over the Svee equations after hisverification of "MSURGE" results.B4-12