Occurrence Of Burnout Research Articles

Self-Determined Motivation as a Predictor of Burnout Among College Athletes

In this study, we examined self-determination theory (SDT; Deci & Ryan, 1985) as a framework for understanding potential antecedents of burnout in 598 American college athletes. Using a cross-sectional design, the aims of the study were to investigate relationships among the dimensions of athlete burnout and the degree of self-determination among college athletes. As hypothesized, results indicated a strong relationship between the degree of self-determination and the dimensions of burnout, thus providing support for the utility of an SDT explanation regarding the occurrence of burnout. Findings also showed motivational variables to be the most powerful predictor of burnout (Devaluation, 44.5%; Reduced Sense of Accomplishment, 28%; Physical/Emotional Exhaustion, 15.4%). Implications of these results for researchers and practitioners are discussed.

Burnout among therapists working with persons with autism after the 2009 earthquake in L'Aquila, Italy: a longitudinal comparative study

The aim of this study was to follow up the occurrence of burnout in therapists of children and adolescents with autism experiencing the 2009 earthquake in L'Aquila, and to discuss implications for burnout prevention after disasters. A longitudinal study was carried out, measuring burnout outcomes according to the Maslach Burnout Inventory in 11 exposed and 53 unexposed therapists. Staff in the exposed group appeared to report significantly higher levels of emotional exhaustion after 1 and 2 years of follow-up than the unexposed staff. As to lack of personal accomplishment, the exposed groups shows increasingly lower scores with respect to the unexposed group, with personal accomplishment (PA) values falling from 41.0 [standard deviation (SD) 3.7] to 33.4 (SD 4.1) after 2 years, whereas PA values remain stable over time in the unexposed group. As to depersonalization, data show no significant difference between groups. Burnout occurrence is induced by the exceptional stressors related with natural disasters like earthquakes. Efforts are required to help mental health workers, including psychiatric nurses, to cope with the devastating situation determined by an earthquake. A periodical monitoring of mental health status is recommended in mental health works, especially with regard to help with post-traumatic stress disorder, coping with work and therapeutic relationships, family and social life and economic impact.

1991 – Burnout syndrome in nurses specialists rehabilitation

Introduction Currently, studies taking into account the incidence of burnout in Nurses Rehabilitation Specialists (NRS) are scarce, a fact which reinforces the need for further investigations in order to be able to understand the real impact of this syndrome in this professional category. This study aimed to determine the occurrence of burnout in NSR and determine whether there is any relationship between the different domains of burnout and sociodemographic aspects, and psychosocial work. Methods We conducted a cross-sectional, quantitative and analytical, which was attended by 117 NSR carrying out functions in various health institutions Portuguese's, aged between 27 and 57 years. To measure the variables used the following instruments: Scale MBI-GS, General Labor Satisfaction Scale, Scale My Health Locus of Control Scale and Levenson's Global Self-Esteem Scale for adults. Results With regard to levels of burnout in NSR conclude that men have higher rates in the dimensions “physical and emotional exhaustion” and “cynicism” compared to women with an average ranking of 11,89 vs 11,57 and 9,56 vs 9,48, respectively; the dimension “professional effectiveness” are women who are more prone to burnout , with an average ranking of 31,20 vs 30,11. The data reveal that there are significant influences of variable working “time professional in the art.” Are obtained also for any significant influences of the psychosocial variables: locus control and self-esteem. Conclusion The evidence found in this study invite us to prepare and reflect on new strategies of intervention training and information aimed at promoting labor welfare of these subjects.

PENGARUH KONFLIK PERAN TERHADAP TERJADINYA BURNOUT PADA MAHASISWA KOASS

Abstract The study was conducted 49 co-ass students who are doing clinical practice (N=49), investigate the effect of role conflict with the occurrence of burnout. Using a purposive technique sampling, these studies make use of two instruments as a measure of role conflict and burnout measurement tools that has been modified from the Maslach Burnout Inventory (MBI) with Likert models. The result is that there is significant influence between role conflict and the occurrence of burnout in co-ass students. The amount of influence (R Square) to the occurrence of role conflict and burnout is 0.389 (38.9%) which means that the conflict affects the role of burnout by 38.9% and the remaining 61.1% influenced by other factors outside of role conflict. This indecated any significant positive effect of role conflict and the occurrence of burnout. Keywords: co-ass, role conflict, burnout

How to achieve in elite training centers without burning out? An achievement goal theory perspective

In training centers, the demonstration of high competence is essential and there is considerable emphasis placed on sporting achievement. Athlete burnout can be a consequence of such pressures and expectations. More information is needed regarding the social, environmental and individual differences in achievement-related characteristics which are relevant to the occurrence of burnout in this context. ObjectivesTo examine the relationships among the coach-created climate, perceived competence, achievement goals and burnout in elite adolescent-age athletes. DesignProspective six-month-follow-up. MethodsData were collected from a sample of 309 young French handball players participating in elite training centers. Cluster analysis and structural equation modeling procedures were employed to evaluate the hypotheses. ResultsComprised of differential scores on the dimensions of burnout, four distinct clusters were identified. Athletes in these cluster groups varied in perceptions of the motivational climate, goal orientations, and perceived competence. The structural model regarding the hypothesized relationships between perceived coach climate, perceived competence, achievement goals and athlete burnout, offered good fit to the data. ConclusionsFindings indicated that young talented athletes perceiving an ego-involving climate and emphasizing mastery avoidance goals at the beginning of the season had a higher risk of experiencing burnout symptoms at the season's end. In contrast, players perceiving a high task-involving climate and emphasizing mastery approach goals at the beginning of the season had lower burnout scores when the season concluded. Moreover, players with high feelings of competence, who also report higher scores on performance approach and avoidance goals, higher scores on mastery approach goals and lower scores on mastery avoidance goals, are less likely to experience burnout.

Síndrome de Burnout entre enfermeiros de um hospital geral da cidade do Recife

Este estudo descritivo, transversal, censitário, identificou Burnout e alguns fatores associados entre enfermeiros da assistência pediátrica e tocoginecológica de hospital geral do nível terciário de atenção do Recife (PE). Participaram 63 profissionais (98,4% do total) que responderam a um questionário auto-aplicável (aspectos sócio-demográficos, condições laborais e Maslach Burnout Inventory). Na análise utilizou-se qui-quadrado, com nível de confiança de 95%. Predominou o gênero feminino (92,1%), com até cinco anos de profissão (68,2%), sendo 52,5% da área pediátrica. Constataram-se altos níveis de exaustão emocional (49,2%) e despersonalização (27,0%) e baixo nível de realização profissional (4,8%), estando 4,7% com Burnout. Mostraram associação: alto nível de exaustão emocional e realizar frequentemente/sempre tarefas com muita rapidez (p=0,039) e receber salário incompatível com o esforço empregado (p=0,016); altos níveis de despersonalização e ter até cinco anos de profissão (p=0,010) e efetuar frequentemente/sempre tarefas com muita rapidez (p=0,009). Para 19,0% pelo menos duas das três dimensões apontavam alta propensão à síndrome.

Burnout y Estrategias de Afrontamiento en Profesores de Educación Básica

Main results from a descriptive-cross sectional study of burnout are reported in this paper. Thc study aimed to identify and describe the burnout phenomenon and the coping strategies used amongst elementary state school teachers in the San Joaquin districl. Both qualitative and quantitative methodologies were used in the data collection and analysis phases of the project. Maslach Burnout Inventory and COPE questionnaires were applied to 103 teachers. Teachers' opinions about the issuc are reported, based on two focus groups. The results suggest a line of action to prevent the occurrence ofburnout.

Mental Health Issues Again Prominent on AMA Agenda

Back to table of contents Previous article Next article Professional NewsFull AccessMental Health Issues Again Prominent on AMA AgendaMark MoranMark MoranSearch for more papers by this authorPublished Online:16 Jul 2010https://doi.org/10.1176/pn.45.14.psychnews_45_14_011AbstractThe AMA House of Delegates approved two reports by the AMA's Council on Science and Public Health (CSAPH) on physician suicide and on lead levels and their effects on children.Without debate or opposition the House approved an extensive report by CSAPH titled “Suicide in Physicians and Physicians-in-Training,” which concluded that “routine occurrence of burnout and mental disorders in physicians and physicians-in-training warrants examination and development of more transparent and efficient solutions.”The report was the result of a resolution brought to the House of Delegates last year by the Section Council on Psychiatry.The council performed a PubMed search of literature from 1970 to March 2010 using the terms “student/medical,” “internship and residency,” and “physicians” in combination with “mortality,” “suicide/epidemiology,” “burnout/professional,” and “stress/psychological.”The council concluded that the periods of medical school and residency are stressful; that many medical students, residents, and practicing physicians experience substantial distress, which contributes to a decline in mental health and well-being; and that physicians often face barriers to the prompt diagnosis and treatment of mental disorders.In response, the council advised the formation of an expert panel to address the subject and develop specific recommendations.“Unfortunately, this is a huge problem among the medical student population,” said Ryan Ribeira, a representative from the Medical Student Section, at reference committee hearings on the report. “It's a personal issue for me as one of my own classmates decided to take his life a year ago, and the year before that a student in the class above me also committed suicide. Across the country I hear the same stories over and over again.... This is a very serious problem, and it is entirely appropriate that the AMA form an expert panel to address this issue.”A second council report, also resulting from a resolution submitted by the Section Council on Psychiatry last year, updates a 1994 report on lead levels in children.APA Treasurer David Fassler, M.D., testifies at the AMA House of Delegates last month in support of a report on health effects of lead in children. The report was the result of a resolution brought to the house by the Section Council on Psychiatry.Credit: Mark MoranThe new report noted that data since 1994 have shown impaired cognition, lowered IQ, and behavioral problems for children exposed to lead at blood concentrations below the Centers for Disease Control and Prevention's current “level of concern” of 10 μg/dL. One analysis of National Health and Nutrition Examination Survey (NHANES) data from 1988 to 2004 showed performance on cognitive tests was diminished in children with blood lead concentrations as low as 2.5 μg/dL.Also, a 2006 analysis of NHANES data specifically evaluated lower blood concentrations as a risk factor for attention-deficit/hyperactivity disorder (ADHD), finding a “significant dose-response relationship” between blood lead concentrations and ADHD.The CSAPH recommended that several policies be updated to reflect the findings of its report and proposed that the following new policy be adopted: “That our AMA urge the Centers for Disease Control and Prevention to give priority to examining the current weight of scientific evidence regarding the range of adverse health effects associated with exposure to blood lead concentrations below the current ‘level of concern’ in order to provide appropriate guidance for physicians and public health policy, and encourage the identification of exposure pathways for children who have low blood lead concentrations, as well as effective and innovative strategies to reduce overall childhood lead exposure.”“This report offers reasonable recommendations based on data available and furthers our overall goal of enhancing awareness [of hazards associated with lead] even at levels currently considered in the acceptable range,” said APA Treasurer David Fassler, M.D., a delegate from the American Academy of Child and Adolescent Psychiatry.Both council reports can be accessed at <www.ama-assn.org/assets/meeting/2010a/a10-annotated-d.pdf>. ISSUES NewArchived

Pertinence des indicateurs de risques psychosociaux à l’hôpital pour la prévention du burnout

L’étude européenne NEXT-PRESST interroge la validité des modèles de la souffrance au travail à partir d’échantillons de soignants de dix pays européens. La réutilisation de ce questionnaire 2008 dans un centre hospitalier universitaire parisien confirme la validité des constats. De plus, l’étude française « Santé et satisfaction des médecins au travail » reprend les mêmes échelles d’analyse pour les médecins. Il est possible de rechercher si les relations retrouvées initialement avec le burnout sont persistantes et de cerner les échelles les plus liées à la survenue du burnout. Des propositions de prévention des risques psychosociaux, valides pour l’ensemble de la communauté soignante, peuvent ainsi être recherchées. Dans ce but, plusieurs relations ont été précisées : entre les scores des modèles de Karasek et Theorell et de Siegrist, de qualité du travail d’équipe et d’incertitude sur les traitements et entre ces scores et le burnout. Les analyses statistiques, réalisées avec le logiciel SPSS 12.0., ont permis de préciser les rôles respectifs de plusieurs dimensions et leurs liens respectifs : dimensions psychosociales du travail, caractéristiques personnelles, équilibre travail/famille, burnout. Selon les analyses multivariées, le modèle de Siegrist et le score de qualité du travail d’équipe sont très pertinents pour prendre en compte les déterminants psychosociaux du stress et du burnout. Les conditions de travail, en particulier le ratio effort / récompense, ont une influence primordiale sur le burnout ; les odds ratios ajustés progressent de 2,00 à 2,88, puis 4,25 avec la dégradation du ratio effort / récompense. Le burnout est particulièrement problématique pour les aides-soignants. Deux autres facteurs explicatifs du burnout, avec pour chacun un gradient clair, selon les niveaux d’exposition, doublent presque sa survenue : la qualité du travail d’équipe et l’exposition à la violence. Les variables décrivant les relations au travail et la circulation de l’information augmentent de 20 % l’occurrence du burnout. Les conflits travail / familles sont aussi essentiels dans son apparition. La situation familiale, en couple avec enfant et surtout seul(e) avec enfant, sont très liée au burnout. Les constats sont confirmés sur la cohorte prospective. Les même facteurs de risque sont retrouvés parmi les médecins avec une ampleur souvent plus grande. La circulation de l’information au sein d’un collectif de travail soudé est primordiale, afin d’améliorer l’influence au travail et la reconnaissance perçue et de réduire le burnout. L’organisation plus efficiente du travail et des repos concertés permettent de réduire le déséquilibre travail / famille. The European study NEXT-PRESST questions the validity of the models of workplace stress from samples of nurses from 10 European countries. The re-use of this 2008 questionnaire in a Parisian University hospital confirms the validity of reports. Furthermore, the French study Health and Satisfaction of Physicians at Work adopted the same scales for physicians. It is possible to find out whether the relations found initially are persistent, and to define propositions for the prevention of psychosocial risks, valid for the whole caring community. With this aim, several relations were clarified: between the scores of Karasek and Theorell's model and of Siegrist's model, quality of the teamwork and uncertainty regarding treatments, and between these four scores and burnout. The statistical analyses, carried out with the software SPSS 12.0. Allowed to clarify the respective roles of several dimensions and their respective links: psychosocial dimensions of the work, personal characteristics, work/ family balance, burnout. According to multivariate analyses, Siegrist's model and quality of teamwork score are very relevant to take into account the psychosocial determinants of stress and burnout. Working conditions, in particular the effort / reward ratio, have an essential influence on burnout ; adjusted odds ratios rise from 2.00 to 2.88, and 4.25 with the degradation of the effort / reward ratio. Burnout is particularly problematic for the nursing aids. Two other explanatory variables for burnout, each with a clear gradient according to exposure levels, almost double its occurrence: quality of the teamwork and exposure to violence. Variables describing the relations at work and the circulation of information increase by 20 % the occurrence of burnout. Among European nurses, the personal situation and especially the work / family conflicts are also essential in its appearance. Family situation, in couple with child and especially single with child, is very much related to burnout. Results are similar to the longitudinal data. The same risk factors are found among physicians often to a larger extent. The circulation of information within a cohesive team is essential to improve the influence at work of each health care worker and the perception of a recognition of his competence. More efficient work organization and association of the health care worker his work rest planning allow to reduce work / family imbalance.

Cognitively Oriented Behavioral Rehabilitation in Combination with Qigong for Patients on Long-Term Sick Leave Because of Burnout: REST—A Randomized Clinical Trial

Despite an increase in the occurrence of burnout, there is no agreement on what kind of rehabilitation these patients should be offered. Primary aim of this study was to evaluate effects on psychological variables and sick leave rates by two different group rehabilitation programs for patients on long-term sick leave because of burnout. Rehabilitation program A (Cognitively oriented Behavioral Rehabilitation (CBR) and Qigong) was compared with rehabilitation program B (Qigong only). In a randomized clinical trial, 96 women and 40 men with a mean age of 41.6 +/- 7.4 years were allocated to one of the two rehabilitation programs. A per-protocol analysis showed no significant difference in treatment efficacy between the groups. Both groups improved significantly over time with reduced levels of burnout, self-rated stress behavior, fatigue, depression, anxiety, obsessive-compulsive symptoms, and sick leave rates. In an intention-to-treat analysis, patients in program A had fewer obsessive-compulsive symptoms and larger effect sizes in self-rated stress behavior and obsessive-compulsive symptoms compared to patients in program B. This study showed no differences in effect between CBR and Qigong compared with Qigong only in a per-protocol analysis. Both rehabilitation programs showed positive effect for patients with burnout.

TEACHER BURNOUT AND JOB SATISFACTION AMONG AGRICULTURAL EDUCATION TEACHERS

The demands on teachers both in and out of classrooms combined with increased budget cuts have led many to question the levels of job satisfaction and burnout among agricultural education teachers. The purpose of this study was to describe the occurrence of burnout and the level at which burnout exists among agricultural education teachers in Ohio. The study was also designed to consider the relationships between job satisfaction, occupational stress, personal strain, personal coping resources, and burnout among agricultural education teachers. A random sample (n = 388) of the population (N = 628) received a mailed questionnaire (37% response, n = 145). Teachers were described predominantly as married, white males with one to two children and less than 10 years of experience in their present positions. The majority of agricultural education teachers in the study possessed high levels of job satisfaction, low levels of occupational stress and personal strain, and high levels of personal coping resources. However, teachers in the study indicated a moderate level of frequency of burnout and a moderate to high level of intensity of burnout. No significant relationships were found between demographic characteristics and burnout, or between organizational factors and burnout.

The role of burnout among Hungarian nurses

This study was aimed to explore the occurrence of burnout among nurses in health and social institutions in Baranya County of Hungary, to reveal the connections between burnout and sociodemographic factors, and to learn its extent in different types of care. The survey was a one-off, representative sample with 805 questionnaires processed. The questionnaire was an internationally used and accepted standard paper designed for assessing burnout syndrome. The sample was given by nurses working in health and social care institutions in 2001. Intensive care nurses have the highest scores for burnout, followed by nurses in long-term care. Active ward nurses show the lowest scores for burnout. Burnout is twice as high among intensive care nurses (10.7%) than among long-term care nurses (3.6%), and the least is among active ward nurses (0.6%). Leaving one's job is closely connected with burnout (66%). Prevention could save health-care workers from burnout and leaving the job independently from nurses' sociodemographic factors.

Burnout in Mothers and Fathers of Children Surviving Brain Tumour

The aim of this paper was to investigate the occurrence of burnout among parents of brain tumour survivors. Burnout was assessed in 24 mothers and 20 fathers of childhood brain tumour survivors, using the Shirom–Melamed Burnout Questionnaire. Parents of children with no history of chronic or serious diseases served as a reference group. Mothers’ burnout scores were significantly higher compared with reference mothers. For fathers, no relation between burnout and being a parent of a brain tumour survivor was established, despite a nonsignificant tendency in the same direction as for the mothers. In conclusion, the parenting burden after a child’s brain tumour may include chronic strain, and this may be particularly taxing for mothers. The findings encourage further studies of psychological exhaustion among parents of children with special needs.

On the occurrence of burnout downstream of a flow obstacle in boiling two-phase upward flow within a vertical annular channel

If a flow obstacle, such as a spacer is placed in a boiling two-phase flow within a channel, the temperature on the surface of the heating tube is severely affected by the existence of the spacer. Under certain conditions, a spacer has a cooling effect, and under other conditions, the spacer causes dryout of the cooling water film on the heating surface. The burnout mechanism, which always occurs upstream of a spacer, however, remains unclear. In a previous paper [Fukano, T., Mori, S., Akamatsu, S., Baba, A., 2002. Relation between temperature fluctuation of a heating surface and generation of drypatch caused by a cylindrical spacer in a vertical boiling two-phase upward flow in a narrow annular channel. Nucl. Eng. Des. 217, 81–90], we reported that the disturbance wave has a significant effect on dryout and burnout occurrence and that a spacer greatly affects the behavior of the liquid film downstream of the spacer. In the present study, we examined in detail the influences of a spacer on the heat transfer and film thickness characteristics downstream of the spacer by considering the result in steam–water and air–water systems. The main results are summarized as follows: (1) The spacer averages the liquid film in the disturbance wave flow. As a result, dryout tends not to occur downstream of the spacer. This means that large temperature increases do not occur there. However, traces of disturbance waves remain, even if the disturbance waves are averaged by the spacer. (2) There is a high probability that the location at which burnout occurs is upstream of the downstream spacer, irrespective of the spacer spacing. (3) The newly proposed burnout occurrence model can explain the phenomena that burnout does occur upstream of the downstream spacer, even if the liquid film thickness t F m is approximately the same before and behind the spacer.

A study on burnout syndrome in healthcare providers to people living with HIV

Dedicating physical and psychological care to other people is a tiring activity, not only because of the responsibility but also, more importantly, because of the emotional aspects involved in this relationship, which lead to stress and, if this stress continues, to burnout syndrome. Some authors report that the demands of caring for HIV-positive people are greater than those for other types of patients, increasing the chances of burnout. This study aimed to investigate the occurrence of burnout in healthcare providers of HIV-positive patients in the state of Paraná, Brazil. Through the use of a questionnaire and the Maslach Burnout Inventory (MBI), 87 people were evaluated. The averages for the MBI were 19.07 for emotional exhaustion (EE), 4.18 for depersonalisation (DE) and 39.60 for personal accomplishment (PA). There were 26.4% of people with high scores on EE, 17.2% presenting elevated DE and 10.5% showing diminished PA in their work. It was observed that the majority of the carers were in this occupation for a short period of time (74.7% for less than five years), while 42.5% spent up to 20 hours per week in the activity. Among the healthcare providers, 63.2% were volunteers. The variables ‘sex’ and ‘working time’ have showed themselves as significant predictors for DE as well as ‘age’ for PA. Taking these characteristics into account, it can be seen that it is necessary to give some special attention to this group of workers, in order to enable them to access preventive and/or interventional measures.

Relation between the occurrence of Burnout and differential pressure fluctuation characteristics caused by the disturbance waves passing by a flow obstacle in a vertical boiling two-phase upward flow in a narrow annular channel

If a flow obstacle such as a spacer is placed in a boiling two-phase flow within a channel, the temperature on the surface of the heating tube is severely affected by the existence of the spacer. Under certain conditions the spacer has a cooling effect, and under other conditions the spacer causes dryout of the cooling water film on the heating surface, resulting in burnout of the tube. The burnout mechanism near the spacer, however, remains unclear. In a previous paper (Fukano, T., Mori, S., Akamatsu, S., Baba, A., 2002. Relation between temperature fluctuation of a heating surface and generation of drypatch caused by a cylindrical spacer in a vertical boiling two-phase upward flow in a narrow annular channel. Nucl. Eng. Des. 217, 81–90), we reported that the disturbance wave has a significant effect on dryout occurrence. Therefore, in the present paper, the relation between dryout, burnout occurrence, and interval between two successive disturbance waves obtained from the differential pressure fluctuation caused by the disturbance waves passing by a spacer, is further discussed in detail.

The relationship between job-related burnout and depressive disorders—results from the Finnish Health 2000 Study

Background Depression and burnout are common health problems in working populations today. They appear to be interrelated, and the need for their differential diagnosis has been highlighted in many reviews. We analysed the overlap of job-related burnout and depressive disorders, i.e., major depressive disorder, dysthymia, and minor depressive disorder. Methods We used the population-based ‘Health 2000 Study’ in Finland. Our nationally representative sample comprised 3276 employees aged 30–64 years. Burnout was assessed with the Maslach Burnout Inventory–General Survey. Diagnoses of depressive disorders were based on the Composite International Diagnostic Interview. Results Burnout and depressive disorders were clearly related. The risk of depressive disorders, especially major depressive disorder (12-month prevalence), was greater when burnout was severe. Half of the participants with severe burnout had some depressive disorder. Those with a current major depressive episode suffered from serious burnout more often than those who had suffered a major depressive episode earlier. Limitations This study was cross-sectional. Conclusions The concepts of burnout and depression complement each other and cover partly overlapping phenomena. Depressive disorders are related to job-related burnout, particularly when it is severe. A current major depressive episode is likely to be associated with the experience of burnout. When encountering working patients, it is recommended to assess both the occurrence of burnout and of depressive disorders.

On the Occurrence of Burnout Downstream of a Flow Obstacle in Boiling Two-Phase Upward Flow within a Vertical Annular Channel.

Abstract If a flow obstacle, such as a spacer is placed in a boiling two-phase flow within a channel, the temperature on the surface of the heating tube is severely affected by the existence of the spacer. Under certain conditions, a spacer has a cooling effect, and under other conditions, the spacer causes dryout of the cooling water film on the heating surface. The burnout mechanism, which always occurs upstream of a spacer, however, remains unclear. In a previous paper [Fukano, T., Mori, S., Akamatsu, S., Baba, A., 2002. Relation between temperature fluctuation of a heating surface and generation of drypatch caused by a cylindrical spacer in a vertical boiling two-phase upward flow in a narrow annular channel. Nucl. Eng. Des. 217, 81–90], we reported that the disturbance wave has a significant effect on dryout and burnout occurrence and that a spacer greatly affects the behavior of the liquid film downstream of the spacer. In the present study, we examined in detail the influences of a spacer on the heat transfer and film thickness characteristics downstream of the spacer by considering the result in steam–water and air–water systems. The main results are summarized as follows: (1) The spacer averages the liquid film in the disturbance wave flow. As a result, dryout tends not to occur downstream of the spacer. This means that large temperature increases do not occur there. However, traces of disturbance waves remain, even if the disturbance waves are averaged by the spacer. (2) There is a high probability that the location at which burnout occurs is upstream of the downstream spacer, irrespective of the spacer spacing. (3) The newly proposed burnout occurrence model can explain the phenomena that burnout does occur upstream of the downstream spacer, even if the liquid film thickness t F m is approximately the same before and behind the spacer.

Influence of a flow obstacle on the occurrence of burnout in boiling two-phase upward flow within a vertical annular channel

When a flow obstruction such as a cylindrical spacer is set in a boiling two-phase flow within an annular channel, the inner tube of which is used as a heater, the temperature on the surface of the heating tube is severely affected by its existence. In some cases, the cylindrical spacer has a cooling effect, and in the other cases it causes the dryout of the cooling water film on the heating surface resulting in the burnout of the heating tube. In the present paper, we have focused our attention on the influence of a flow obstacle on the occurrence of burnout of the heating tube in boiling two-phase flow. The results are summarized as follows: (1) When the heat flux approaches the burnout condition, the wall temperature on the heating tube fluctuates with a large amplitude. And once the wall temperature exceeds the Leidenfrost temperature, the burnout occurs without exception. (2) The trigger of dryout of the water film which causes the burnout is not the nucleate boiling but the evaporation of the base film between disturbance waves. (3) The burnout never occurs at the downstream side of the spacer. This is because the dryout area downstream of the spacer is rewetted easily by the disturbance waves.

Relation between the Occurrence of Burnout and Differential-Pressure Fluctuation Characteristics Caused by the Disturbance Waves Passing by a Flow Obstacle in a Vertical Boiling Two-Phase Upward Flow in a Narrow Annular Channel.

If a flow obstacle such as a spacer is set in a boiling two-phase flow within an annular channel, where the inner tube is used as a heater, the temperature on the surface of the heater tube is severely affected by the existence of the spacer. In some case the spacer has a cooling effect, and in the other case it causes the dryout of the cooling liquid film on the heating surface resulting in the burnout of the tube. The burnout mechanism near the spacer, however, is not still clear. In the present paper we focus our attention on the occurrence of the burnout near a spacer, and discuss the occurrence location of dryout and burnout and the relation between the occurrence of burnout and differential-pressure fluctuation characteristics caused by the disturbance waves passing by a spacer.