Comparative Performance Metric Assessment of A Military Turbojet Engine Utilizing Hydrogen And Kerosene Fuels Through Advanced Exergy Analysis Method

Abstract

This study dealt with evaluating the (J85-GE-5H) military turbojet engine (TJE) in terms of exergetic and advanced exergetic analyses at Military (MIL) and Afterburner (AB) process modes by utilizing kerosene (JP-8) and hydrogen (H2) fuels. First, exergy and advanced exergy analyses of the engine were performed using JP-8 fuel as per actual engine operating conditions. These analyses of the turbojet engine using hydrogen fuel were also examined parametrically. The performance evaluation of the engine was lastly executed by comparing the obtained results for both fuels. Based on the parametric studies undertaken, the entire engine’s exergetic efficiency with JP-8 was reckoned 30.85% at the MIL process mode while it was calculated as 16.98% at the AB process mode. With the usage of H2, the efficiencies of the engine decreased to 28.62% and 15.33% for the above mentioned two modes, respectively. As the supreme exergy destructions occurred in the combustion chamber (CC) and afterburner exhaust duct (ABED) segments, the new technological developments should be considered to design more efficient engines. As a result, the engine worked less efficiently with hydrogen fuel due to the enhancement in exergy destructions. Conversely, the greenhouse gas (GHG) emission parameters lessened with the utilization of H2 fuel.

Assessing Exergy-Based Economic and Sustainability Analyses of a Military Gas Turbine Engine Fueled with Various Fuels

“…Ex D rates were reckoned at 11,447 kW (41.21 GJ/h) and 41,920 kW (151 GJ/h) for the MIL and AB PM, seriatim. The TJE's exergetic efficiency was determined 16.98% and 30.85% for the AB and MIL PM, seriatim [63]. The lowest SEF was reckoned in the CC section with the rate of 2.20 for the MIL PM, while it was computed to be 2.13 in the ABED section for the AB PM.…”

“…The power output was reckoned with the values of 5106 and 8575 kW for the MIL and AB PM, seriatim [63]. The take-off thrust is 25.80 kN, the outside diameter of the TJE is 0.52 m, the engine length is 2.75 m, the engine weight is 265 kg, the flight speed range is 301-1004 m/s, the maximum operating altitude is 45,000 ft and the starting altitude range is 0-25,000 ft [64].…”

“…The experimental throughput has been displayed in the control unit in order to trace values such as pressure (P), mass rates ( m  ) and temperature (T), which have been obtained by indicators attached on the TJE. As the engine worked in the engine test cell, the inlet duct was not taken into account in the analysis [63]. The physicochemical properties of JP-8 and H2 are indicated as follows:…”

“…The cost of equipment and the hourly cost rates are shown in Table 3. Tables A1 and A2 indicate the rates of energy, exergy, mass flow, pressure and specific heat capacity for the TJE sections, seriatim, in Appendix A [63]. The equations respecting exergy and cost balance are denoted in Table 4.…”

“…The performance metrics of the TJE respecting exergy, sustainability and exergoeconomic are assigned in Table 5 [6,37,44,49,63].…”