Optimization of turboprop ESFC and NOx emissions for UAV sizing

Abstract

Purpose This paper aims to present a genuine code developed for multi-objective optimization of selected parameters of a turboprop unmanned air vehicle (UAV) for minimum landing-takeoff (LTO) nitrogen oxide (NOx) emissions and minimum equivalent power specific fuel consumption (ESFC) at loiter (aerial reconnaissance phase of flight) by using a genetic algorithm. Design/methodology/approach The genuine code developed in this study first makes computations on preliminary sizing of a UAV and its turboprop engine by analytical method for a given mission profile. Then, to minimize NOx emissions or ESFC or both of them, single and multi-objective optimization was done for the selected engine design parameters. Findings In single objective optimization, NOx emissions were reduced by 49 per cent from baseline in given boundaries or constraints of compressor pressure ratio and compressor polytropic efficiency in the first case. In second case, ESFC was improved by 25 per cent from baseline. In multi-objective optimization case, where previous two objectives were considered together, NOx emissions and ESFC decreased by 26.6 and 9.5 per cent from baseline, respectively. Practical implications Variation and trend in the NOx emission index and ESFC were investigated with respect to two engine design parameters, namely, compressor pressure ratio and compressor polytropic efficiency. Engine designers may take into account the findings of this study to reach a viable solution for the bargain between NOx emission and ESFC. Originality/value UAVs have different flight mission profiles or characteristics compared to manned aircraft. Therefore, they are designed in a different philosophy. As a number of UAV flights increase in time, fuel burn and LTO NOx emissions worth investigating due to operating costs and environmental reasons. The study includes both sizing and multi-objective optimization of an UAV and its turboprop engine in coupled form; compared to manned aircraft.

A sizing tool for the preliminary design of an unmanned aerial vehicle for student projects

“…A simplified algorithm and equations for aircraft size and weight calculations was presented in a previous work [2]. This methodology was derived from many references in literature [3][4][5][6][7][8][9][10][11][12]. Clearly, the design process is a trial-and-error process to get the best design per the requirements such as highest flight score, the highest payload and the lowest possible empty weight while still making sure that the aircraft still fits inside the given box physically.…”

Preliminary design of a radio-controlled micro aircraft for student competition

“…Preliminary design of an aircraft starts with initial size and weight estimates. A simplified algorithm for aircraft size and weight calculation is presented here [2][3][4][5][6][7][8][9][10][11]. Some assumptions on parameters (weight of payload, payload fraction, wing loading, aspect ratio) need to be made for start.…”

Performance Assessment of a Medium-Scale Turboprop Engine Designed for Unmanned Aerial Vehicle (Uav) Based on Exergetic and Sustainability Metrics

“…The fuel (3) and air (2) are mixed and burned in the combustion process which also raised the enthalpy of working fluid (2)(3)(4). The combustion gases (4-5) are expanded throughout the GT to produce the mechanical work that drives the AC via the GTMS (8)(9). After that, the combustion gases (5-6) are dilated through the PT to generate the mechanical power that rotates the propeller with PTMS (10-11).…”

“…If the weight of an armed UAV is considered in company with flight range and envelope, an electromotor is insufficient to power the UAV. For this reason, turbine engines are commonly preferred in military UAVs such as MQ-9 Reaper, RQ-4 Global Hawk, TAI ANKA, General Atomics Avenger and so on [5][6][7][8][9][10][11].…”