G2 Gas Fitter Practice Exam 2025 - Free Gas Fitter Practice Questions and Study Guide

The component that determines the direction of the gas stream down the center of a Venturi in an atmospheric burner is the Venturi tube. The Venturi tube operates under the principle of fluid dynamics, where the shape of the tube causes the gas to accelerate as it moves through a narrowed section.

As the gas enters the Venturi, it experiences a decrease in pressure and an increase in velocity due to the tube's converging design. This process effectively draws the gas toward the center of the tube, optimizing the mixing of gas and air for combustion. By ensuring that the gas stream is directed through the center, the Venturi tube plays a crucial role in maintaining efficient and stable burner operation.

In contrast, while air shutters can adjust the amount of air mixed with the gas, they do not directly influence the direction of the gas flow itself. A gas flow meter measures the flow rate but does not affect the flow direction, and a pressure regulator is primarily concerned with managing the pressure of the gas but does not control its trajectory in the burner system. Thus, the Venturi tube is the key component for directing the gas stream within an atmospheric burner setup.