A、壓降小,管網(wǎng)效率就低;壓降大,效率就高 B、壓降小,管網(wǎng)效率就高;壓降大,效率也高 C、壓降小,管網(wǎng)效率就高;壓降大,效率就低 D、管網(wǎng)效率的大小與壓力大小元關(guān)
A、[△pQ/3.6P]x100% B、[p/(p+△p)]x(Q△Q) C、p/(p+△p)x100% D、Q/Q△Qx100%
A、相角 B、功率因數(shù) C、三角函數(shù) D、轉(zhuǎn)數(shù)