Which type of burner is typically not mixed until it leaves the burner port?

The nozzle mixing burner is designed to combine fuel and air at the burner port rather than before it. In this type of burner, fuel is introduced into the airflow stream as it exits the nozzle. This allows for better control of the combustion process and can lead to higher efficiency and more stable flames. The operational principle behind this design is to enhance the mixing of fuel and air right before combustion occurs, which results in a more complete and efficient burn.

In contrast, the pre-mixed burner combines air and fuel before they reach the burner port, which ensures a well-mixed gas-air mixture prior to ignition. Jet burners also blend fuel and air but typically do so in a way that promotes mixing before ignition in a different manner compared to nozzle mixing burners. Fuel-efficient burners may have various designs focusing on reducing fuel consumption, but they do not specifically describe the mixing process as the nozzle mixing burner does.