Comparison of Nozzle Vs. Impeller Agitation in Quench Systems

While many quench tanks use propellers to promote fluid motion, other systems pump the quenchant through a series of small nozzles. Although propeller based systems are in one sense more straightforward, direct connection to external drive systems and internal flow control devices to guide the flow put considerable constraints on system design. In contrast, pumped systems require less space inside the quench tank and provide the opportunity to more directly apply the quench flow to the part surfaces. Due to piping system losses, however, less agitation may be provided for a given amount of input power.

As a comparison of these approaches, CFD analyses are performed of idealized propeller and nozzle systems to determine their ability to generate flow for a given input power. Typical quench tank arrangements with both impeller and nozzle systems are also simulated, and the near surface velocities achieved for a representative part will be assessed.