I'm having problems with what seems like a simple Bernoulli exercise where I can plug in all known variables but not get an answer (using Excel). If I reduce my system down, it would be exactly like a venturi/pipe flow problem except that flow is in the direction of small pipe to large pipe. P1 and A1 are for small pipe, P2 and A2 are for larger pipe. P1=60psi A1=.002in^2 (very small orifice) P2=55psi A2=.307in^2 density (rho) air at 90F/60psi=.367lb/ft^3 Bernoulli's eqn at continuity gives flow rate Q = A2*[((2*deltaP)/rho)/(1-(A2/A1)^2)]^0.5 When I plug in the numbers as shown, I get a number error in Excel because the 1-(A2/A1)^2 in the denominator ends up negative. Any ideas where I might have gone wrong? Thanks very much.