考慮過渡沸騰效應的液滴流膜沸騰一維半經驗物理模型之發展

Development of a One-dimensional Semi-empirical Model Considering Transition Boiling Effects For Dispersed Flow Film Boiling

王予柔(Wang, Yu Jou)

指導教授 ： 潘欽

國立清華大學/原子科學院/核子工程與科學研究所/碩士(2016年)

摘要

本研究提出一個考慮過渡沸騰的乾化後液滴流膜沸騰的一維半經驗物理模型，此模型由四個守恆式組成 (液滴動量、液滴質量、蒸汽質量、蒸汽能量)，及相關的組合方程式以考慮液滴流膜沸騰中所有的熱傳方式與其熱傳率。
將模型預測的結果與文獻中的實驗結果作比較，現有的模型可以成功地預測壁面溫度上升的幅度及熱不平衡的情況，且在壓力介於30~140 bar,熱通量204~1837 kW/m2 及質量通率 380~5180 kg/m^2s 的流動條件下，可得到準確的預估結果於方均根(Root mean square) 8.8% 與標準差 8.81%中，證實了本模型的適用性。研究結果指出過渡沸騰區的影響對後乾化模式的準確度十分重要，不可忽略。同時，本研究進一步以靈敏度分析方法探討不同壓力、質量流率與熱通率對於液滴流膜沸騰熱傳的影響，結果呈現了不同流動情況下的液滴受熱量與蒸汽溫度，以探討於不同流動情況之下的熱不平衡現象。

關鍵字

液滴流膜沸騰 ； 後乾化模式 ； 過度沸騰 ； 熱不平衡

並列摘要

The objective of this paper is to develop a one-dimensional semi-empirical model for the dispersed flow film boiling considering transition boiling effects. The proposed model consists of conservation equations, i.e. vapor mass, vapor energy, droplet mass and droplet momentum conservation, and a set of closure relations to address the interactions among wall, vapor and droplets. The results show that transition boiling effect is of vital importance in the dispersed flow film boiling regime, since the flowing conditions in the downstream would be influenced by the conditions in the upstream. In addition, the present paper, through evaluating the vapor temperature and the amount of heat transferred to droplets, investigates the thermal non-equilibrium phenomenon under different flowing conditions. Comparison of the wall temperature predictions with the 1394 experimental data in the literature, the present model ranging from system pressure of 30~140 bar, heat flux of 204~1837 and mass flux of 380~5180 , shows very good agreement with RMS of 8.80% and standard deviation of 8.81% . Moreover, the model well depicts the thermal non-equilibrium phenomenon for the dispersed flow film boiling.

並列關鍵字

dispersed flow film boiling ； post-dryout ； transition boiling ； thermal-nonequilibrium

參考文獻

1. G.L. Yoder and W.M. Rohsenow, A solution for dispersed flow heat transfer using equilibrium fluid conditions, Journal of Heat Transfer, 105(1) (1983) 10-17.

2. L.S. Tong and Y.S. Tang, Boiling heat transfer and two-phase flow, CRC press, 1997.

3. J.D. Parker and R.J. Grosh, Heat transfer to a mist flow, Argonne National Laboratory, 1961.

4. R.P. Forslund and W.M. Rohsenow, Dispersed flow film boiling, Journal of Heat Transfer, 90(4) (1968) 399-407.

5. A.W. Bennett, G.F. Hewitt, H.A. Kearsey and R.K.F. Keeys, Heat Transfer To Steam-Water Mixtures Flowing In Uniformly Heated Tubes In Which The Critical Heat Flux Has Been Exceeded, Atomic Energy Research Establishment, Harwell, Eng., 1968.