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Article
Publication date: 15 July 2020

Wenbin Gao, Weifeng Huang, Tao Wang, Ying Liu, Zhihao Wang and Yuming Wang

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, an effective method to study the flow field of…

Abstract

Purpose

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, an effective method to study the flow field of the mechanical seal when both cavitation and boiling exist simultaneously is found.

Design/methodology/approach

Based on the finite volume method, a fluid model was developed to investigate a two-phase mechanical seal. The validity of the proposed model was verified by comparing with some classical models.

Findings

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, the analysis of the gap flow field of the mechanical seal was realized when cavitation and boiling existed simultaneously.

Originality/value

Based on the model proposed for different conditions, the pressure and phase states in the shallow groove sealing gap were compared. The phase change rate between the mechanical seal faces was also investigated.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0537/

Details

Industrial Lubrication and Tribology, vol. 72 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 April 1996

V.R. Voller, P. Felix and C.R. Swaminathan

Cyclic phase change involves the successive freezing and melting of aregion driven by a boundary temperature that cycles above and below thesolid/liquid phase change

Abstract

Cyclic phase change involves the successive freezing and melting of a region driven by a boundary temperature that cycles above and below the solid/liquid phase change temperature. In this paper, a recently proposed fixed grid phase change enthalpy method is modified and applied to cyclic solid/liquid phase change problems. The basic approach is demonstrated on application to a one‐dimensional, heat conduction controlled phase change. Then the method is used to investigate a cyclic phase change problem that involves fluid flow. The interaction of the melting and freezing with the phase change leads to some interesting predictions for the location and shape of the solid/liquid interface. The results also indicate that melting cycles are more effective than freezing cycles.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 6 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Book part
Publication date: 6 August 2018

Forrest Briscoe and Sean Safford

This paper develops an argument about how contentious changes unfold in organizational fields, focusing on the role of uncertainty – and the networks people use to address…

Abstract

This paper develops an argument about how contentious changes unfold in organizational fields, focusing on the role of uncertainty – and the networks people use to address uncertainty. We propose that as controversial practice gains traction and spreads, the nature of uncertainty facing organizational decision makers also evolves. This dynamic has important implications for how different actors and networks can influence change. We illustrate our argument with a mixed-methods case study on the diffusion of domestic partner benefits across US Fortune 500 companies. Our findings shed light on how – and when – social activists, corporate elites, and middle managers can influence the corporate decision-making process.

Details

Social Movements, Stakeholders and Non-Market Strategy
Type: Book
ISBN: 978-1-78754-349-2

Keywords

Article
Publication date: 5 December 2020

Mampe Kumalo and Caren Brenda Scheepers

Organisational decline has far-reaching, negative emotional and financial consequences for staff and customers, generating academic and practitioner interest in turnaround…

Abstract

Purpose

Organisational decline has far-reaching, negative emotional and financial consequences for staff and customers, generating academic and practitioner interest in turnaround change processes. Despite numerous studies to identify the stages during turnarounds, the findings have been inconclusive. The purpose of this paper is to address the gap by defining these stages, or episodes. The characteristics of leaders affect the outcome of organisational change towards turnarounds. This paper focusses, therefore, on the leadership requirements during specific episodes, from the initial crisis to the full recovery phases.

Design/methodology/approach

A total of 11 semi-structured interviews were conducted with executives from the public sector in South Africa who went through or were going through turnaround change processes and 3 with experts consulting to these organisations.

Findings

Contrary to current literature in organisational change, this study found that, in these turnaround situations, leadership in the form of either an individual CEO or director general was preferable to shared leadership or leadership distributed throughout the organisation. This study found four critical episodes that occurred during all the public service turnarounds explored, and established that key leadership requirements differ across these episodes. The study shows how these requirements relate to the current literature on transactional, transformational and authentic leadership.

Practical implications

The findings on the leadership requirements ultimately inform the selection and development of leaders tasked with high-risk turnaround change processes.

Originality/value

Four episodes with corresponding leadership requirements were established in the particular context of public sector turnaround change processes.

Details

Journal of Organizational Change Management, vol. 34 no. 1
Type: Research Article
ISSN: 0953-4814

Keywords

Article
Publication date: 1 March 1989

Nicholas S. Rashford and David Coghlan

Kubler‐Ross′ stages of death and dying – denial, anger,bargaining, depression and acceptance‐have formed the basis of much ofthe therapeutic work with the terminally ill…

2869

Abstract

Kubler‐Ross′ stages of death and dying – denial, anger, bargaining, depression and acceptance‐have formed the basis of much of the therapeutic work with the terminally ill. As death and dying are the ultimate instances of change in a person′s life, it is hypothesised that Kubler‐Ross′ work has an application to the theory and process of change. A four‐stage model of organisational change‐denying, dodging, doing and sustaining – based on Kubler‐Ross is presented. These four stages are linked to the four organisational levels, generating a seven‐phase framework that integrates the complex interplay of denying, dodging, doing and sustaining in the individual, the team, the group and the organisation.

Details

Journal of Managerial Psychology, vol. 4 no. 3
Type: Research Article
ISSN: 0268-3946

Keywords

Article
Publication date: 1 March 1996

Hongjun Li, C.K. Hsieh and D.Y. Goswami

A method has been developed for conjugate heat transfer analysis offluid flow inside parallel channels formed by a phase change material (PCM)separated from the fluid by a…

Abstract

A method has been developed for conjugate heat transfer analysis of fluid flow inside parallel channels formed by a phase change material (PCM) separated from the fluid by a wall. The phase change in the PCM is two dimensional and a hybrid analysis consisting of an analytical solution in one direction and a finite‐difference method in another direction is used to solve for the temperature in the PCM. The heat transfer fluid (HTF) inlet temperature is given and the heat transfer between the HTF and the PCM is treated as a conjugate problem that requires no iterations to obtain a solution. The numerical results are found to be stable, convergent, and accurate. Application of the method to the solution of heat extraction from a phasechange energy storage unit is given in detail and the numerical results are shown to be accurate, based on an energy conservation analysis, to within 3%.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 6 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 March 1995

Roger Stuart

Describes research into managers′ experiences of significantorganizational change attempts. The research project was aimed atdeveloping frameworks which: describe…

5336

Abstract

Describes research into managers′ experiences of significant organizational change attempts. The research project was aimed at developing frameworks which: describe, illuminate and enable a better understanding of managers′ journeys through organizational change; serve as a template for bringing together the very diverse and fragmented literature relating to individuals experiencing change; highlight issues and pointers for the design and facilitation of effective organizational change initiatives. The first part describes the context, spirit, intentions, sample and methodology of the research. Also, reviews a broad range of literature which can inform our understanding of individuals in change. Propounds the need to open up the “real world” of organizational change, as perceived and experienced by managers, rather than any “ideal” view of how that world is desired or supposed to be. Presents and discusses research findings on the sensed and initiating “primary” triggers for change‐that is, the formal and communicated organizational change objectives; and the perceived and felt “secondary” triggers for change‐that is, the issues raised by, and the implications of, the organizational changes for individual managers. The second part presents a framework depicting the phases and components of managers′ journeys through organizational change. On the framework, the experience of managers can be located, in terms of their thoughts, feelings and behaviours, as the processes of change unfold. While each manager′s journey was found to be unique, the framework proved to be ubiquitous in enabling the mapping of all the managers′ journeys, and it also accommodates literature on phenomena as diverse as learning, personal transition, catastrophe and survival, trauma and stress, loss and “death”, and worry and grief. The findings emphasize the profoundness and deeply felt emotionality of many managers′ experiencing of change in organizations. Finally, identifies the outcomes of managers′ journeys through significant attempts at organizational change. Also presents the reported helping and hindering factors to those journeys. Implications of these findings are pursued, particularly in terms of the leadership and development roles and behaviours required, if the organization and its management are to move beyond simply requiring change towards actively facilitating its achievement.

Details

Personnel Review, vol. 24 no. 2
Type: Research Article
ISSN: 0048-3486

Keywords

Article
Publication date: 1 February 1988

Kumar K. Tamma and Sudhir B. Railkar

The present paper describes the applicability of hybrid transfinite element modelling/analysis formulations for non‐linear heat conduction problems involving phase change

Abstract

The present paper describes the applicability of hybrid transfinite element modelling/analysis formulations for non‐linear heat conduction problems involving phase change. The methodology is based on application of transform approaches and classical Galerkin schemes with finite element formulations to maintain the modelling versatility and numerical features for computational analysis. In addition, in conjunction with the above, the effects due to latent heat are modelled using enthalpy formulations to enable a physically realistic approximation to be effectively dealt computationally for materials exhibiting phase change within a narrow band of temperatures. Pertinent details of the approach and computational scheme adapted are described in technical detail. Numerical test cases of comparative nature are presented to demonstrate the applicability of the proposed formulations for numerical modelling/analysis of non‐linear heat conduction problems involving phase change.

Details

Engineering Computations, vol. 5 no. 2
Type: Research Article
ISSN: 0264-4401

Article
Publication date: 1 August 1996

DIEGO CELENTANO and EMILIO PÉREZ

A phasechange temperature‐based formulation including general latent heat effects is presented. These effects are taken into account by means of an explicit “phasechange

Abstract

A phasechange temperature‐based formulation including general latent heat effects is presented. These effects are taken into account by means of an explicit “phasechange function” (or liquid fraction‐temperature relationship in a more specific context) defined analytically or based on experimental measurements. The behaviour of different functions is studied and compared. The finite element equations of this formulation are also described. Finally, a numerical example is analysed to illustrate the performance of the proposed methodology.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 6 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 February 2006

Zhanhua Ma and Yuwen Zhang

To study the effects of velocity correction schemes for a temperature transforming model (TTM) for convection controlled solid‐liquid phasechange problem.

Abstract

Purpose

To study the effects of velocity correction schemes for a temperature transforming model (TTM) for convection controlled solid‐liquid phasechange problem.

Design/methodology/approach

The effects of three different solid velocity correction schemes, the ramped switch‐off method (RSOM), the ramped source term method (RSTM) and the variable viscosity method (VVM), on a TTM for numerical simulation of convection controlled solid‐liquid phasechange problems are investigated in this paper. The comparison is accomplished by analyzing numerical simulation and experimental results of a convection/diffusion phasechange problem in a rectangular cavity. Model consistency of the discretized TTM is also examined in this paper. The simulation results using RSOM, RSTM and VVM in TTM are compared with experimental results.

Findings

In order to efficiently use the discretized TTM model and obtain convergent and reasonable results, a grid size must be chosen with a suitable time step (which should not be too small). Applications of RSOM and RSTM‐TTM yield identical results which are more accurate than VVM.

Originality/value

This paper provides generalized guidelines about the solid velocity correction scheme and criteria for selection of time step/grid size for the convection controlled phase change problem.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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