scholarly journals The Effect of Uneven Heating On the Flow Distribution Between Parallel Microchannels Undergoing Boiling

2021 ◽  
Author(s):  
Ankur Miglani ◽  
Anali Soto ◽  
Justin A. Weibel ◽  
Suresh V. Garimella
Keyword(s):  
Flow Distribution ◽  
Power Input ◽  
Input Power ◽  
Distribution Model ◽  
Component Level ◽  
Two Phase ◽  
And Performance ◽  
Parallel Microchannels ◽  
Uneven Heating ◽  
The Impact

Abstract As the size, weight, and performance requirements of electronic devices grow increasingly demanding, their packaging has become more compact. As a result of thinning or removing the intermediate heat spreading layers, non-uniform heat generation from the chip-scale and component-level variations may be imposed directly on the attached microchannel heat sink. Despite the important heat transfer performance implications, the effect of uneven heating on the flow distribution in parallel microchannels undergoing boiling has been largely unexplored. In this study, a two-phase flow distribution model is used to investigate the impact of uneven heating on the flow distribution behavior of parallel microchannels undergoing boiling. Under lateral uneven heating (i.e., the channels are each heated to different levels, but the power input is uniform along the length of any given channel), it is found that the flow is significantly more maldistributed compared to the even heating condition. Specifically, the range of total flow rates over which the flow is maldistributed is broader and the maximum severity of flow maldistribution is higher. These trends are assessed as a function of the total input power, degree of uneven heating, and the extent of thermal connectedness between the channels. These model predictions are validated against experiments for a representative case of thermally isolated channels subjected to even heating and extreme lateral uneven heating conditions and show excellent agreement.

scholarly journals Accountability legislation: Implications for financial and performance reporting

2012 ◽  
Vol 1 (1) ◽  
pp. 25-35
Author(s):  
Daphne Rixon
Keyword(s):  
Public Sector ◽  
Stakeholder Management ◽  
The Body ◽  
Second Phase ◽  
Theoretical Frameworks ◽  
Two Phase ◽  
Performance Reporting ◽  
Accountability Legislation ◽  
And Performance ◽  
The Impact

The purpose of this case study is to first examine the implications of accountability legislation on the financial and performance reporting of a public sector agency in the Canadian province of Newfoundland and Labrador and secondly, to compare the level of accountability with Stewart’s (1984) ladder of accountability. This paper is based on the first phase of a two-phase study. The first phase focuses on the initial impacts of accountability legislation on agencies and the challenges created by the legislation’s ‘one size fits all’ approach. The second phase of this study will examine the impact of the legislation on stakeholders after it has been in operation for five years. The second phase will include interviews with stakeholders to ascertain the level of satisfaction with the new legislation. The first phase of the study is significant since it highlights how governments could consider stakeholder needs when drafting such legislation. This research contributes to the body of literature on stakeholder accountability since there is a paucity of research focused specifically on the impact of accountability legislation on public sector agencies. An important contribution of this paper is the introduction of a framework for legislated accountability reporting. The main theoretical frameworks used to analyse the findings are Stewart’s (1984) ladder of accountability in conjunction with Friedman and Miles (2006) ladder of stakeholder management and engagement.

The Numerical Simulation and Performance Analysis of the Vortex Pump for Solid-Liquid Two Phase Medium

2014 ◽  
Vol 527 ◽  
pp. 88-92
Author(s):  
Peng Yun Song ◽  
Hong Li Wang ◽  
Peng Cheng He
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Internal Flow ◽  
Solid Particles ◽  
Two Phase ◽  
Pump Head ◽  
Phase Medium ◽  
And Performance ◽  
Solid Liquid ◽  
The Impact

The numerical simulation of a 3-D model of the internal flow field for a Vortex slurry pump has been analyzed in this paper. The impact of different solids volume fraction on the distribution of solid particle was analyzed. The expression of the pump head and efficiency was derived by the energy equation. The results show that either on the long blades or on the short blades, the content of the solid particles increases with the increasing of the volume fraction. The results by the expression of the pump head and efficiency are compared with the results of the simulations. The conclusions show that the expression results are similar with the numerical simulation results, and the main factors of affecting the inner and outer characteristics are the solid particles.

Parametric Single Gap Turbine Rim Seal Model With Boundary Generation for Asymmetric External Flow

2010 ◽  
Author(s):  
M. Hu¨ning
Keyword(s):  
Discharge Coefficient ◽  
Peak Pressure ◽  
Geometric Mean ◽  
Flow Distribution ◽  
Underlying Mechanism ◽  
Flow Stagnation ◽  
Proposed Model ◽  
Sensitivity Studies ◽  
And Performance ◽  
The Impact

In an effort to provide predictions for hot annulus ingestion flows across turbine rim seals into rotor-stator wheel-space cavities, this paper describes a parametric single gap turbine rim seal model, which contains of several different sub- or part-models. Annulus pressure variations are the underlying mechanism driving ingestion. Some of the sub-models are matched to published experimental results. The model results are compared with measurements from different test rigs. The proposed model calculates the annulus boundary conditions based on geometric, mean turbine aerodynamic and performance parameters for the rim seal under consideration. Special attention is paid to the modelling of the flow stagnation upstream of airfoils as a row of half-bodies and the local seal gap discharge coefficient in order to assess the flow distribution through the rim seal. Mixing zones are accounted by a mixing cascade modelling. The peak pressure attenuation behaviour around the seal is considered. Sensitivity studies, e.g. for the impact of annulus boundary layer thickness, are performed.

scholarly journals Study of the sealing elements impact on air flow distribution in a seed vessel of seeding mechanism

2018 ◽  
Vol 224 ◽  
pp. 05015
Author(s):  
Anton Yu. Popov ◽  
Denis K. Muratov
Keyword(s):  
Model Building ◽  
Air Flow ◽  
Flow Simulation ◽  
Flow Distribution ◽  
Distribution Model ◽  
Software Environment ◽  
Velocity Change ◽  
Aerodynamic Model ◽  
The Impact ◽  
Sealing Elements

The quality of the pneumatic seeding mechanism operation is defined by a variety of factors, including aerodynamic characteristic quantities. But aerodynamics of seeding systems is poorly studied. Therefore studying of the air flow distribution in a seeding mechanism seed vessel is considered to be a current issue. Overpressure seeding mechanism with a seed vessel compulsory sealing is approved as the object of the studying. The aim of the studying is to define the impact of the sealing elements shape on the air flow distribution in a seed vessel by various seeding mechanism operating modes. The building-up of the air flow distribution model is carried out at the software environment Solidworks Flow Simulation with allowance for a seeding wheel rotation. The aerodynamic model building-up technique is given. The graphic charts of airflow velocity change in an upper part of the seed vessel are made. The designed overpressure seeding mechanism aerodynamic model is analyzed.

The Impact of Property Characteristics on Economic Performance of Russian Industrial Enterprises

2005 ◽  
pp. 53-68 ◽  
Author(s):  
R. Kapeliushnikov ◽  
N. Demina
Keyword(s):  
Detailed Analysis ◽  
Economic Performance ◽  
Ownership Concentration ◽  
Corporate Sector ◽  
Concentrated Ownership ◽  
Industrial Enterprises ◽  
Russian Industry ◽  
Control Premium ◽  
And Performance ◽  
The Impact

The paper provides new survey evidence on effects of concentrated ownership upon investment and performance in Russian industrial enterprises. Authors trace major changes in their ownership profile, assess pace of post-privatization redistribution of shareholdings and provide evidence on ownership concentration in the Russian industry. The major econometric findings are that the first largest shareholding is negatively associated with the firm’s investment and performance but surprisingly the second largest shareholding is positively associated with them. Moreover, these relationships do not depend on identity of majority shareholders. These results are consistent with the assumption that the entrenched controlling owners are engaged in extracting "control premium" but sizable shareholdings accumulated by other blockholders may put brakes on their expropriating behavior and thus be conductive for efficiency enhancing. The most interesting topic for further more detailed analysis is formation, stability and roles of coalitions of large blockholders in the corporate sector of post-socialist countries.

The Impact of Women’s Employment on Marital Stability in Qatar Society

2019 ◽  
Vol 10 (2) ◽  
pp. 144-151
Author(s):  
Noora Ahmed Lari ◽  
Keyword(s):  
Work Motivation ◽  
Marital Stability ◽  
Female Employment ◽  
Social Constraints ◽  
Primary Data ◽  
Family Policies ◽  
Insufficient Time ◽  
And Performance ◽  
The Impact ◽  
The Relationship

The State of Qatar has implemented several family policies in order to improve the wellbeing of Qatari families and ensure fair distribution of development benefits for both men and women. However, there is a linkage between female employment outside the home and instability in the marriages of Qatari families. This paper investigates the impact of female employment on marital stability, based on the results of primary data collected in Qatar, a questionnaire that consisted of several sections such as challenges in the workplace, supervisor, family and spouse relations, work motivation and performance. Of the 824 questionnaires that were returned, 807 were completed and valid for analysis. Regression analysis and an ANOVA test have been used to test the relationship between the variables. The results of the research have produced mixed findings about how wives’ employment increases marital instability and have yielded few significant differences on mean scores of discuss on work demands, insufficient time together, housework, financial matters, communication, relatives and rearing children. The results indicates that in general Qatar working women face several challenges in relation to their marital life as part of cultural and social constraints.

The Role of Research and Innovation in the Transformation of Agri-Food Systems

2018 ◽  
Vol 12 (2) ◽  
pp. 60-63
Author(s):  
Mariana Sandu ◽  
Stefan Mantea
Keyword(s):  
Technological Progress ◽  
Food Systems ◽  
Food System ◽  
Agricultural Research ◽  
Research And Innovation ◽  
And Performance ◽  
The Impact ◽  
Determinant Factor ◽  
Rapid Transformation

Abstract Agri-food systems include branching ramifications, which connect in the upstream the input suppliers with farmers, and downstream farmers, processors, retailers and consumers. In the last decades, at the level of the regions, food systems have undergone rapid transformation as a result of technological progress. The paper analyzes the changes made to the structure, behavior and performance of the agri-food system and the impact on farmers and consumers. Also, the role of agricultural research as a determinant factor of transformation of agri-food system is analyzed. The research objective is to develop technologies that cover the entire food chain (from farm to fork) and meet the specific requirements of consumers (from fork to farm) through scientific solutions in line with the principles of sustainable agriculture and ensuring the safety and food safety of the population.

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