STEADY-STATE ANALYSIS OF FLUID CIRCUITS CONTAINING 3 PORT DEVICES

An improved implementation of the Newton-Raphson method for the static analysis of fluid networks has been developed. This now allows circui ts containing three and four terminal non-linear devices to be analyse d. One type of multi-port device that is used to control ventilation c ircuits is the vortex amplifier. This is a three terminal (supply, con trol and outlet) controller with no moving parts. Vortex amplifier cha racteristics have been integrated into a ForTran steady state network analysis program which has been used successfully for designing ventil ation systems controlled by these devices. Any form of pipe and device resistance can be defined. Experience of using this program has shown that the geometry of the network and the relative positions of high a nd low resistance pipework and devices can prevent numerical convergen ce. A more detailed examination of this has provided two methods of ov ercoming this non-convergence.