Fuel turbine flowmeter

The fuel system of the aircraft engine test bench is an important component of the test bench process system, used to provide continuous and uninterrupted fuel supply for the required pressure and flow rate of the engine. It generally has functions such as pressure regulation, filtration, and metering.

As one of the important parameters for evaluating engine performance, the fuel consumption rate of the engine requires that fuel flow measurement should minimize external influences and reflect the actual fuel consumption of the engine as accurately as possible. The high-precision dual rotor turbine flowmeter, as a velocity based flow measurement instrument, has the advantages of high measurement accuracy, wide measurement range, strong anti-interference ability, and pulse output. It is widely used in the fuel flow measurement of aircraft engine test benches to meet the requirements of real-time and accurate measurement of engine fuel consumption.
The turbine flowmeter is mainly composed of the flowmeter housing, turbine rotor, front and rear guide vanes of the turbine rotor, clamping ring, induction coil, and permanent magnet. When fuel flows through the turbine flowmeter, the fuel flowing in the pipeline drives the axial rotation of the turbine rotor, and the speed of the turbine rotor increases with the increase of fuel flow rate. The turbine rotor cuts the magnetic field lines of the permanent magnet, and the induction coil detects the electromagnetic signal of the turbine rotor and converts it into a readable frequency, current or voltage signal, which is transmitted to the backend instrument for accumulation or display.

In an ideal working state, there is a proportional relationship between the volumetric flow rate qv of the turbine flowmeter and the pulse frequency F of the signal output by the turbine flowmeter, that is: qv=F ÷ K (1)
In the formula: K is the coefficient of the turbine flowmeter instrument, L-1； F is the pulse frequency output by the turbine flowmeter.  
In an ideal working state, the instrument constant K of the turbine flowmeter is a constant value. During use, the instrument constant of the turbine flowmeter is a function of the external flow state, fluid viscosity, fluid temperature, fluid pressure, etc., that is, K=f (qv, t, P, τ).