How can you improve combustion efficiency and reduce emissions?

1 Understand the combustion process

The first step to improve combustion efficiency and reduce emissions is to understand the underlying physical and chemical processes that govern the combustion phenomenon. Combustion is a complex and nonlinear process that involves multiple phases, modes, and regimes, depending on the fuel type, oxidizer type, mixture ratio, pressure, temperature, and flow conditions. You need to analyze the thermodynamics, kinetics, fluid dynamics, and heat transfer of the combustion process to identify the optimal operating conditions and the sources of inefficiency and emissions. You can use analytical, numerical, and experimental tools to model, simulate, and test the combustion process and validate your results.

2 Optimize the fuel and oxidizer properties

The second step to improve combustion efficiency and reduce emissions is to optimize the fuel and oxidizer properties to match the combustion requirements and constraints. The fuel and oxidizer properties include their physical state, composition, purity, density, viscosity, volatility, heating value, flame speed, ignition delay, and stability. You need to select the fuel and oxidizer that can provide the highest energy output, the lowest ignition energy, the fastest combustion rate, and the least amount of harmful emissions. You can also modify the fuel and oxidizer properties by blending, reforming, doping, or adding additives to enhance their performance and compatibility.

3 Control the fuel and oxidizer injection

The third step to improve combustion efficiency and reduce emissions is to control the fuel and oxidizer injection to achieve the optimal mixture distribution and atomization. The fuel and oxidizer injection affects the mixing quality, droplet size, spray angle, penetration depth, and evaporation rate of the reactants, which in turn influence the combustion initiation, propagation, and termination. You need to design the injector geometry, configuration, orientation, location, and number to optimize the injection parameters and ensure a uniform and homogeneous mixture. You can also use active or passive techniques to modulate the injection flow rate, pressure, velocity, and direction to adapt to the changing combustion conditions.

4 Enhance the combustion stability

The fourth step to improve combustion efficiency and reduce emissions is to enhance the combustion stability to prevent unwanted fluctuations, oscillations, instabilities, or blowouts. Combustion stability is affected by the feedback mechanisms between the heat release, pressure, temperature, and flow fields in the combustion chamber, which can lead to acoustic, thermoacoustic, or hydrodynamic phenomena that can disrupt the combustion process. You need to monitor the combustion dynamics and detect the signs of instability using sensors, actuators, and controllers. You can also use passive or active methods to dampen, suppress, or eliminate the instabilities by modifying the chamber geometry, acoustic impedance, or combustion feedback.

5 Reduce the combustion losses

The fifth step to improve combustion efficiency and reduce emissions is to reduce the combustion losses that result from incomplete combustion, heat transfer, or friction. Incomplete combustion occurs when the fuel and oxidizer are not fully reacted, leaving unburned hydrocarbons, carbon monoxide, or soot in the exhaust. Heat transfer occurs when the combustion heat is dissipated to the chamber walls, nozzle, or surroundings, reducing the available energy for propulsion. Friction occurs when the combustion products encounter resistance from the chamber walls, nozzle, or shock waves, reducing the exhaust velocity and thrust. You need to minimize the combustion losses by improving the combustion completeness, insulation, and expansion.

6 Implement the emission control technologies

The sixth step to improve combustion efficiency and reduce emissions is to implement the emission control technologies that can reduce or eliminate the pollutants generated by the combustion process. The main pollutants of concern are nitrogen oxides (NOx), carbon dioxide (CO2), water vapor (H2O), and particulate matter (PM), which can have adverse effects on the climate, health, and visibility. You need to select the emission control technologies that can target the specific pollutants and their formation mechanisms, such as catalytic converters, selective catalytic reduction, exhaust gas recirculation, water injection, fuel staging, or lean premixed prevaporized combustion.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?