Gas turbine engines, ramjet engines, internal combustion engines, liquid rocket engines and other engines for aerospace propulsion systems involve complex gas-liquid two-phase flow and combustion. The spray combustion process in these engines include multiple physical and chemical processes such as atomization, evaporation, mixing and combustion. Spray combustion may face extreme ambient conditions such as low temperature, high speed, flame-limit equivalence ratio, super criticality and constrained space, as well as efficient and stable operating requirements for combustion in a wide range of off-designed conditions. These factors present new challenges for stable combustion and the associated organization methods.

Using both experiments and numerical simulations, researchers need to explore the spray combustion mechanism inside engines and put forward an organization method for effective and adaptable combustion, which is essential to improve efficiency and emission control. At the same time, spray combustion is still essential to guarantee stable operation and maximize the development and performance of new power technologies and detonation engines, such as pre-cooled combined power, turbo-aided rocket-augmented ramjet combined cycle engines (TRRE), rocket-based combined cycle engines (RBCC) and turbine-based combined cycle systems (TBCC).

This Special Issue aims to collect original research and review articles which focus on two-phase flow, chemical reaction kinetics and combustion organizations that are common in all types of engines in the aerospace industry. We welcome the discussion of original concepts but also encourage authors to integrate issues such as gas-liquid two-phase flow and combustion in engines with other disciplines, providing new ideas for the development of theories and technologies in two-phase flow and combustion for propulsion systems in the aerospace industry.

Potential topics include but are not limited to the following:

• The mechanism of spray and evaporation in engines
• Atomization in transverse jet and its mixing enhancement in supersonic flow
• Micro- and nano-scale multiphase flow and heat and mass transfer
• Mathematical modelling and numerical simulation of two-phase flow
• Reactive two-phase flow test and measurement technology
• Turbulent spray combustion interaction mechanism
• Experimental, numerical and model studies of strong turbulent combustion
• Theory and application of combustion reaction kinetics in extreme conditions
• Unsteady combustion process in engines
• New two-phase fuel and propellant technology for aerospace propulsion