Typically, the supply flow of fluids enter it along the peripheral perimeters of a central cylinder to be drawn radially and differentially in terms of fluid kinetic energies to the central parts of the cylinder from where the fluid exits axially along the exit throat or diffuser (King, 1987). The mechanism that creates the differentials between the kinetic energies of the entering fluid and the exiting one is the core functional part of the device. The efficiency of the device depends on its ability to destroy the kinetic energies of the entering flows by generating a vortex. that also helps create the required kinetic energies of the exiting flows (King, 1987).
Typically, a control flow also enters the peripheral parts of the central cylinder to meet the supply flow tangentially, modulating its kinematic characteristics and inducing it to move to the central parts of the cylinder in a free vortex (King, 1987). The kinetic energies of the control flow increases that of the supply flow and the total flow ends up in the central parts of the cylinder in a free vortex. The turbulent interactions at the downstream parts of the exit throat ultimately destroys parts of the total kinetic energies of the flow and only the exiting flow is allowed out with only the required kinematic characteristics (King, 1987). ...
Here, as is evident later on in the report, kinematic characteristics signify those applicable to fluid pressure and flow rate.
2. Performance Characteristics:
The v.a. (vortex amplifier) modulates two fluid flow characteristics - pressure and flow rate (King, 1987). For pressure control the 'control pressure ratio' is important while for flow rate control the 'turn down ratio' is (King, 1987).
2.1 Control Pressure Ratio:
The control pressure ratio (G) is derived as:
G = (pressure drop from control inlet to outlet)/(pressure drop from supply inlet to outlet)
For v.a. performance the value of G that corresponds to the 'cutoff control flow' G* is the most crucial and G* is the maximum pressure applicable by control flows when the supply flow is zero (King, 1987). Thus, G* is often used to measure the efficiency of the v.a. in providing resistance to supply flows.
2.2 Turn Down Ratio:
The turn down ratio (T) is derived as:
T = (supply flow rate when control flow rate is zero)/(control flow rate when supply flow rate is zero)
Technically, the above derivation implies the ratio of the maximum flow rate to the minimum one gives the turn down ratio (King, 1987).
2.3 Performance Index:
The performance index (T/G*) represents the ability of the v.a. to generate a high turn down ratio with a low control one (King, 1987). Typically, a v.a. designer aims either at a high T or a low G* or both. It is usual that a high T is achieved by sacrificing a high G* and a low T with that of a low G* (King, 1987). Thus, T/G* remains one of the major performance indicators of vortex amplifiers (King, 1987).
The report has presented the functional and performance characteristics of the triodic vortex