A stationary device used to divert the flow of flue gases is known as what?

A baffle is a stationary device specifically designed to divert the flow of flue gases within a system, such as a furnace or boiler. Its primary function is to enhance the efficiency of the appliance by directing the gases in a controlled manner. This can help in improving heat exchange by ensuring that flue gases move through the heat exchanger more efficiently, thereby maximizing heat transfer and combustion efficiency.

The other options do not fulfill the same function as a baffle. A duct is typically used for the purpose of transporting air or gases but does not specifically divert flow within a system. A flue refers to the passage or channel for flue gases to exit a appliance but does not have a mechanism to divert the flow. Venturi refers to a device that uses fluid dynamics principles to create a pressure drop in a flowing fluid, thus not serving the purpose of diverting flue gases as intended in this context.