# Fuel-Water Emulsions as an Alternative Fuel for Gas Turbines: A Project Summary
## 2 Subject and Methodology of Research
### Research Stand  
On the test stand, the GTM120 gas turbine was placed on a platform, allowing it to move together with the turbine relative to the base in the direction opposite to the thrust vector. This movement was made possible by linear bearings and two guides. Mounting the engine on the stand in the manner described enables the measurement of thrust, which was carried out with the NS-6 strain gauge beam from Mavin (the WDT-1 strain gauge sensor amplifier from WObit was used) (Figure 3). In the engine inlet, in a 2' characteristic cross-section (Figure 4), the static temperature (Czaki TP-202, NiCr-NiAl), static pressure (Kobold SEN-8701/2 B045) and dynamic pressure (Honeywell ASDX030D44R) were measured. Temperatures (Czaki TP-202 and TP-203) and static pressures (Kobold SEN-8701/2 B055 and Kobold SEN-8701/2 B045) were measured in sections 3' and 4'. Behind the engine, in a 9' cross-section, there is a Testo 350 exhaust gas analyzer probe and a Czaki TP-203 thermocouple attached to it. Fuel consumption is measured indirectly by measuring the change in the pressure of the liquid column in the tank, which occurs with the consumption of fuel by the engine. The Dudek P400U differential pressure transmitter was used for the measurement. Data acquisition from the sensors was performed via a National Instruments USB-6259 BNC measurement card. The measurement uncertainties (catalogs) of the sensors used are presented in Tables 1 and 2.  
Figure 3: Test stand: close-up of the GTM120 gas turbine.  
Due to the concern that the addition of water or other additives may adversely affect the lubricating properties of the mixture, it was decided to modify the factory lubrication system (Figure 5a) in such a way that a standard fuel mixture was used to lubricate the bearings (Figure 5b). In the factory fuel system, after being pumped through the fuel pump, the fuel with oil added is divided into two flows using a tee and an orifice installed in the fuel system. About 97.5% of the fuel mixture is directed to the combustion chamber, while the remaining part is used in the open lubrication system. For the purposes of testing, the fuel system was separated from the lubrication system. The lines responsible for supplying the mixture to the bearings were disconnected from the system and then connected to an additional fuel tank, which contained a standard mixture of fuel and oil, regardless of the type of mixture being burned. The mixture was pumped from it to the lubrication system using an additional fuel pump. The fuel pump was voltage-controlled by pulse width modulation. During the preliminary tests, there was no impact of the mass flow of the lubricating mixture on the measured parameters.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Sensor** & **Uncertainty of Measurement** \\ \hline Thrust & NS-6 + WDT-1 & \(\pm\)0.55 N \\ Pressure & Kobold SEN-8701/2 B045 & \(\pm\)2.50 kPa \\ Pressure & Kobold SEN-8701/2 B055 & \(\pm\)4.00 kPa \\ Pressure & Dudek P400U & \(\pm\)34.0 Pa \\ Pressure & Honeywell ASDX030D44R & 4.14 kPa \\  & - in the range of \(-\)40 \(\div\) 375 \({}^{\circ}\)C: \(\pm\)1.5 \({}^{\circ}\)C \\ Temperature & Thermocouple NiCr-NiAl & - in the range 375 \(\div\) 1000 \({}^{\circ}\)C: \(\pm\)0.4\% of \\  & & the measured value \\ \hline \hline \end{tabular}
\end{table}
Table 1: Measurement uncertainties of the sensors.  
Figure 4: Cross-section of the engine with cross-section numbering (from [38]).