Thermal-mixing flow characteristics of mixing valve

Mixing valves play an important role in fluid transmission pipeline systems and fluid heat mixing in the chemical-energy industry. To limit thermal fatigue cracking failure of cross-combination pipelines and thermal-mixing equipment, this study investigated the effect of plunger strokes on the internal flow and temperature fluctuation of a mixing valve. A large eddy simulation method was used to study the temperature distribution and fluctuation mechanism of a fluid during hot mixing using a mixing valve with different plunger strokes. For mixing valves, the centroid of the effective jet section of the branch pipe moves to the negative Y-axis during plunger stroke operations, resulting in a jet angle change in the branch pipe. As the effective jet area of the branch pipe decreases, the vortex structure of the branch pipe also changes. When the plunger stroke is small, there is a higher and stronger temperature fluctuation in the 90 degrees circumferential area of the wingspan section, whereas when the plunger stroke is large, there is a higher and stronger temperature fluctuation in the 270 degrees circumferential area of the wingspan section. The results showed that valve operation should be avoided at these plunger strokes and monitoring at these positions is required during operation. The study results provide an industry reference for the internal hot-mixing flow characteristics of mixing equipment with adjustable flow channels.