Effects of Rotor Disc Growth on Flow and Heat Transfer Characteristics of Rim Seal

2017 ◽  
Author(s):  
Xingyun Jia ◽  
Qun Zheng ◽  
Hai Zhang ◽  
Yuting Jiang
Keyword(s):  
Heat Transfer ◽  
Flow Characteristic ◽  
Operating Conditions ◽  
Heat Transfer Characteristics ◽  
Hot Gas ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Actual Operating ◽  
Thermal Growth ◽  
Structure Thickness

Under actual operating conditions of gas turbine, centrifugal and thermal growth of disc in radial direction result in dislocation of inflow boundary at the disc mid-radius height, and a radial step of platform at high radius height. In this paper, flow and heat transfer characteristics in dislocated rim seal region are analyzed by the conjugate and thermal mechanical numerical methods. The calculated radial growths of turbine discs reach approximately 14–20 % of turbine platform structure thickness. Dislocation of rim seal structure directly affects the flow characteristic of externally-induced (EI) ingress and rotationally-induced (RI) ingress, and aggravates overheat of stator disc due to induced hot gas ingestion, further affects the loss of mixture of mainstream gas and cooling sealant air flow in rim-seal and wheelspace regions. Radial step between rotor and stator platforms exacerbates the area and depth of hot gas ingestion in seal clearance, along with a 2–7 % decrease in seal efficiency.

Air Side Heat Transfer Characteristics of Wavy-Finned-Tube in a Forced Draft Direct Air-Cooled Steam Condenser

2012 ◽  
Vol 516-517 ◽  
pp. 3-8
Author(s):  
Zhao Ying Zhang ◽  
Jian Guo Yang ◽  
Hai Zhen Zhang
Keyword(s):  
Heat Transfer ◽  
Environmental Temperature ◽  
Finned Tube ◽  
Operating Conditions ◽  
Heat Transfer Characteristics ◽  
Power Generating Unit ◽  
Transfer Characteristics ◽  
Actual Operating ◽  
Forced Draft ◽  
Face Velocity

An experimental study was performed on wavy-finned-tube used in forced draft direct air-cooled steam condenser (DACSC) under actual working conditions of the power generating unit. Tests were carried out to study the air side heat transfer characteristics of wavy-finned-tube in actual operating conditions of DACSC, such as: air temperature, air face velocity, environmental temperature, exhaust pressure of steam turbine and temperature of exhaust steam. The air-side heat transfer characteristics of wavy-finned-tube heat exchangers were tested and analyzed by varying air face velocity .One empirical correlations for predicting the h-factor was developed.

scholarly journals Uncertainties Analysis on the Prediction of Flow and Heat Transfer of Liquid Sodium with CFD Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhanwei Liu ◽  
Xinyu Li ◽  
Tenglong Cong ◽  
Rui Zhang ◽  
Lingyun Zheng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Liquid Sodium ◽  
Heat Transfer Characteristics ◽  
Backward Facing Step ◽  
Heating Wall ◽  
Transfer Characteristics ◽  
Cfd Models ◽  
Flow And Heat Transfer

The prediction of flow and heat transfer characteristics of liquid sodium with CFD technology is of significant importance for the design and safety analysis of sodium-cooled fast reactor. The accuracies and uncertainties of the CFD models should be evaluated to improve the confidence of the numerical results. In this work, the uncertainties from the turbulent model, boundary conditions, and physical properties for the flow and heat transfer of liquid sodium were evaluated against the experimental data. The results of uncertainty quantization show that the maximum uncertainties of the Nusselt number and friction coefficient occurred in the transition zone from the inlet to the fully developed region in the circular tube, while they occurred near the reattachment point in the backward-facing step. Furthermore, in backward-facing step flow, the maximum uncertainty of temperature migrated from the heating wall to the geometric center of the channel, while the maximum uncertainty of velocity occurred near the vortex zone. The results of sensitivity analysis illustrate that the Nusselt number was negatively correlated with the thermal conductivity and turbulent Prandtl number, while the friction coefficient was positively correlated with the density and Von Karman constant. This work can be a reference to evaluate the accuracy of the standard k-ε model in predicting the flow and heat transfer characteristics of liquid sodium.

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