Jiaxing Ren , Ruohao Wang , Fangdong Wang , Weiqiang Xu , Ruifeng Tian , Puzhen Gao , Shouxu Qiao , Sichao Tan
{"title":"带间隔栅杆束空气-水气泡流相分布特性的实验研究","authors":"Jiaxing Ren , Ruohao Wang , Fangdong Wang , Weiqiang Xu , Ruifeng Tian , Puzhen Gao , Shouxu Qiao , Sichao Tan","doi":"10.1016/j.pnucene.2025.105801","DOIUrl":null,"url":null,"abstract":"<div><div>This study investigates the phase distribution characteristics of upward adiabatic air-water bubbly flow in a vertical 5 × 5 rod bundle with a spacer grid. A four-sensor conductivity probe is used to measure the detailed local cross-sectional distribution of interfacial parameters, including void fraction, interfacial area concentration, Sauter mean diameter, and bubble velocity in twelve bubbly flow conditions at five axial elevations. The core-peak and gap-peak distribution patterns of void fraction and interfacial area concentration in individual subchannels are observed through cross-sectional measurements. The bubble size distribution is relatively uniform, and the bubble velocity peak is consistently located at the subchannel center. The transition from core-peak to gap-peak distributions occurs with increasing superficial liquid velocity and decreasing superficial gas velocity. During this process, a dual peak appears temporarily before converging into a stable single peak in the subchannel edge. The effects of the spacer grid on phase distribution are discussed in detail. Cross-flow causes a shift in the local peaks and enhances bubble exchange between subchannels, resulting in a more uniform distribution of the entire cross-section. The mixing vanes significantly increase the overall void fraction within a very short distance, approximately 1–2 <em>D</em><sub><em>h</em></sub> downstream of the spacer grid. Using the improved cross-sectional area-averaging method, the one-dimensional distribution of interfacial parameters is obtained to analyze the transport characteristics in rod bundles. The spacer grid causes an increase in interfacial area concentration by promoting bubble breakup, as confirmed by the axial distribution of bubble size. The combined effects of the spacer grid are critical for predicting thermal-hydraulic parameters in nuclear safety analysis. Based on the present experimental study, its influence gradually diminishes around 20 <em>D</em><sub><em>h</em></sub> downstream in bubbly flow.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"186 ","pages":"Article 105801"},"PeriodicalIF":3.3000,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Experimental study on characteristics of phase distribution in air-water bubbly flow in a rod bundle with spacer grid\",\"authors\":\"Jiaxing Ren , Ruohao Wang , Fangdong Wang , Weiqiang Xu , Ruifeng Tian , Puzhen Gao , Shouxu Qiao , Sichao Tan\",\"doi\":\"10.1016/j.pnucene.2025.105801\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>This study investigates the phase distribution characteristics of upward adiabatic air-water bubbly flow in a vertical 5 × 5 rod bundle with a spacer grid. A four-sensor conductivity probe is used to measure the detailed local cross-sectional distribution of interfacial parameters, including void fraction, interfacial area concentration, Sauter mean diameter, and bubble velocity in twelve bubbly flow conditions at five axial elevations. The core-peak and gap-peak distribution patterns of void fraction and interfacial area concentration in individual subchannels are observed through cross-sectional measurements. The bubble size distribution is relatively uniform, and the bubble velocity peak is consistently located at the subchannel center. The transition from core-peak to gap-peak distributions occurs with increasing superficial liquid velocity and decreasing superficial gas velocity. During this process, a dual peak appears temporarily before converging into a stable single peak in the subchannel edge. The effects of the spacer grid on phase distribution are discussed in detail. Cross-flow causes a shift in the local peaks and enhances bubble exchange between subchannels, resulting in a more uniform distribution of the entire cross-section. The mixing vanes significantly increase the overall void fraction within a very short distance, approximately 1–2 <em>D</em><sub><em>h</em></sub> downstream of the spacer grid. Using the improved cross-sectional area-averaging method, the one-dimensional distribution of interfacial parameters is obtained to analyze the transport characteristics in rod bundles. The spacer grid causes an increase in interfacial area concentration by promoting bubble breakup, as confirmed by the axial distribution of bubble size. The combined effects of the spacer grid are critical for predicting thermal-hydraulic parameters in nuclear safety analysis. Based on the present experimental study, its influence gradually diminishes around 20 <em>D</em><sub><em>h</em></sub> downstream in bubbly flow.</div></div>\",\"PeriodicalId\":20617,\"journal\":{\"name\":\"Progress in Nuclear Energy\",\"volume\":\"186 \",\"pages\":\"Article 105801\"},\"PeriodicalIF\":3.3000,\"publicationDate\":\"2025-05-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Progress in Nuclear Energy\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0149197025001994\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"NUCLEAR SCIENCE & TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Progress in Nuclear Energy","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0149197025001994","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"NUCLEAR SCIENCE & TECHNOLOGY","Score":null,"Total":0}
Experimental study on characteristics of phase distribution in air-water bubbly flow in a rod bundle with spacer grid
This study investigates the phase distribution characteristics of upward adiabatic air-water bubbly flow in a vertical 5 × 5 rod bundle with a spacer grid. A four-sensor conductivity probe is used to measure the detailed local cross-sectional distribution of interfacial parameters, including void fraction, interfacial area concentration, Sauter mean diameter, and bubble velocity in twelve bubbly flow conditions at five axial elevations. The core-peak and gap-peak distribution patterns of void fraction and interfacial area concentration in individual subchannels are observed through cross-sectional measurements. The bubble size distribution is relatively uniform, and the bubble velocity peak is consistently located at the subchannel center. The transition from core-peak to gap-peak distributions occurs with increasing superficial liquid velocity and decreasing superficial gas velocity. During this process, a dual peak appears temporarily before converging into a stable single peak in the subchannel edge. The effects of the spacer grid on phase distribution are discussed in detail. Cross-flow causes a shift in the local peaks and enhances bubble exchange between subchannels, resulting in a more uniform distribution of the entire cross-section. The mixing vanes significantly increase the overall void fraction within a very short distance, approximately 1–2 Dh downstream of the spacer grid. Using the improved cross-sectional area-averaging method, the one-dimensional distribution of interfacial parameters is obtained to analyze the transport characteristics in rod bundles. The spacer grid causes an increase in interfacial area concentration by promoting bubble breakup, as confirmed by the axial distribution of bubble size. The combined effects of the spacer grid are critical for predicting thermal-hydraulic parameters in nuclear safety analysis. Based on the present experimental study, its influence gradually diminishes around 20 Dh downstream in bubbly flow.
期刊介绍:
Progress in Nuclear Energy is an international review journal covering all aspects of nuclear science and engineering. In keeping with the maturity of nuclear power, articles on safety, siting and environmental problems are encouraged, as are those associated with economics and fuel management. However, basic physics and engineering will remain an important aspect of the editorial policy. Articles published are either of a review nature or present new material in more depth. They are aimed at researchers and technically-oriented managers working in the nuclear energy field.
Please note the following:
1) PNE seeks high quality research papers which are medium to long in length. Short research papers should be submitted to the journal Annals in Nuclear Energy.
2) PNE reserves the right to reject papers which are based solely on routine application of computer codes used to produce reactor designs or explain existing reactor phenomena. Such papers, although worthy, are best left as laboratory reports whereas Progress in Nuclear Energy seeks papers of originality, which are archival in nature, in the fields of mathematical and experimental nuclear technology, including fission, fusion (blanket physics, radiation damage), safety, materials aspects, economics, etc.
3) Review papers, which may occasionally be invited, are particularly sought by the journal in these fields.