What protects the interior surface of the combustor dome from high temperatures?

The interior surface of the combustor dome is protected from high temperatures primarily through the use of a cooling air film. This cooling air film is created by directing cooling air into the combustor area. As the high-temperature combustion gases flow through the combustor, the cooling air forms a protective layer on the interior surfaces, which helps dissipate heat away from the combustor materials and maintain their structural integrity. This method is crucial as it ensures that the components do not exceed their temperature limits, which could lead to damage or failure.

While other options, such as a heat shield or protective coating, provide varying degrees of protection, the cooling air film is specifically designed to manage the extreme heat generated during combustion, making it highly effective for this application.