Thermal effect on mass flow-rate of sonic nozzle

• Main Authors: Ding Hong-Bing, Wang Chao, Wang Gang
• Format: Article
• Language: English
• Published: VINCA Institute of Nuclear Sciences 2018-01-01
• Series: Thermal Science
• Subjects: sonic nozzle; thermal effect; thermal boundary-layer; constrained thermal deformation
• Online Access: http://www.doiserbia.nb.rs/img/doi/0354-9836/2018/0354-98361600146D.pdf

Sonic nozzles are widely used as flow measurement and transfer standard. The thermal effect of sonic nozzle is significant at low Reynolds number. It includes two correction factors, CT for the thermal boundary-layer and Cα for constrained thermal deformation of throat area. Firstly, using the similarity solution, the formula for correction factor CT over wall temperature range from 0.8T0 to 1.2T0 was obtained. For γ = 1.33, CT = 1 – 3.800 Re–1/2ΔT/T0; for γ = 1.4, CT = 1 – 3.845 Re–1/2ΔT/T0; for γ = 1.67, CT = 1 – 4.010 Re–1/2ΔT/T0. Secondly, thermal and stress models for partially constrained expansion were built. Unlike the free expansion, truth slopes of Cα for three nozzles are +1.74·10–6, –2.75·10–5 and –3.61·10–5, respectively. Lastly, the experimental data of Cu nozzle was used to validate present results. It revealed that modified experimental values are in good agreement with the present result.