Quadratic unconstrained binary optimization for environmental control system equipment design and assessment

Abstract This paper explores possible implementations of a quantum annealing-based algorithm, in the Quadratic unconstrained binary optimization method (QUBO) form, to solve the thermo-fluid dynamics problem associated with the design of critical components of aircraft environmental control systems, namely compact heat exchangers and ejectors (also known as jet pumps), used on rotary- or fixed- winged aircrafts environmental control system to mix two fluids and exchange thermal energy. The purpose of this paper is to introduce the implementation of the QUBO model based on compact heat exchangers lumped model and the SAE 1168–6 ejector design procedure, with the formalization of the mathematical problem and the comparison of results obtained with experimental tests, classical resolution approaches and the quantum optimized code, showing how the QUBO approach is an effective and efficient tools for design engineers tasked to design and validate equipment parameters.We start with a simple two-phase flow within a single-pass mini-channel heat exchanger, describing the mathematical formulation of the problem followed by a simplified implementation of the proposed quantum approaches, highlighting the main procedures of the calculation as well as the practical implications, advantages and disadvantages of the proposed method, e.g. a limited number of CFD simulations are required to evaluate air side heat transfer coefficient and pressure drop for particular designs within the defined design space, and the specific hardware required to implement the quantum process.