Thermally choked flow occurs when the addition of heat to a compressible fluid flow in a duct or channel causes the flow velocity to reach the local speed of sound at some point. Further heat addition will then not increase the flow rate; instead, it leads to adjustments in upstream conditions. The process of determining the parameters at which this condition arises involves analyzing the interplay between energy input, fluid properties, and duct geometry. For instance, consider air flowing through a heated pipe; as heat is added, the air accelerates. At the location where the Mach number reaches unity, a thermal choke is established.
Understanding and predicting this phenomenon is vital in various engineering applications, including the design of combustion chambers, rocket nozzles, and high-temperature gas pipelines. Accurately predicting the onset of a thermally choked condition can prevent catastrophic failures and optimize system performance. Historically, empirical correlations were used, but modern computational fluid dynamics (CFD) and analytical techniques provide more accurate and detailed predictions.
