Search results

This study focuses on the CFD numerical simulation and analysis of the vortex stacking problem at the top of the impeller of a high-speed fuel pump, mainly using LCS and entropy production theory to visualize the vortex at the top of the impeller as well as quantitatively analyzing the energy loss caused by the vortex at the top of the impeller. By combining the two methods, the two are well verified with each other that the stacking problem of the vortex at the top of the impeller and the location of the energy loss caused by the vortex are consistent with the vortex location. Such a method can reveal the problem of vortex buildup at the top of the lobe well, and provide a novel guidance idea for improving the performance of high-speed fuel pumps.

Based on CFD numerical simulation and analysis, this study mainly uses LCS and entropy production theory to visualize the top vortex of the impeller. Through the combination of the two methods, the accumulation problem of the top vortex of the impeller and the location of the energy loss caused by the vortex can be well revealed.

(1) The CFD numerical simulation analysis of the high-speed fuel pump is carried out, and the test is conducted to verify the numerical simulation results. The inlet and outlet pressure difference? P is used as the validation index, and the error analysis shows that the error between numerical simulation and test results is within 10%, which meets our requirements. Therefore, we carry out the next analysis with the help of CFD numerical simulation. By analyzing the full working condition simulation, its inlet and outlet differential pressure? P and efficiency? Are evaluated. It is found that its differential pressure decreases with the flow rate and its efficiency reaches its maximum at Qv = 9.87 L/s with a maximum efficiency of 78.32%. (2) We used the LCS in the analysis of vortices at the top of the impeller blades of a high-speed fuel pump. One of the metrics used to describe the LCS in fluid dynamics is the FTLE. The high FTLE region represents the region with the highest and fastest particle trajectory stretching velocity in the fluid flow. We performed a cross-sectional analysis of the FTLE field on the different height surfaces of the impeller on 25% Plane, 50% Plane, and 75% Plane, respectively. And a quarter turn of the rotor rotation was analyzed as a cycle divided into 8 moments. It is found that on 25% Plane, the vortex at the top of the lobe is not obvious, but there are high FTLE values on the shroud surface. On 50% Plane, the lobe top vortex is relatively obvious and the number of vortices is three. The vortex pattern remains stable with the rotating motion of the rotor. At 75% Plane, the lobe top vortex is more visible and its number of vortices increases to about 5 and the vortex morphology is relatively stable. The FTLE ridges visualize the vortex profile. This is a good guide for fluid dynamics analysis. (3) At the same time, we use the entropy production theory to quantitatively analyze the energy loss, and define the entropy production rate Ep. Through the entropy production analysis of the impeller shroud surface and the suction surface of the pressure surface of the blades at eight moments, we find that the areas of high energy loss are mainly concentrated in the leading and trailing edges of the blades as well as in the shroud surface close to the leading edge of the blades, and the value of the entropy production rate is up to 106 W/m3/K. The areas of high energy loss in the leading edge of the blades as well as the trailing edge show a curved arc, and the energy loss is decreasing as it moves away from the shroud surface and closer to the hub surface. The high energy loss areas at the leading and trailing edges of the blades are curved, and the energy loss decreases as they move away from the shroud surface and closer to the hub surface. The energy loss at the pressure surface of the blade is relatively small, about 5 × 105 W/m3/K, which is mainly concentrated near the leading edge of the blade near the shroud surface and the trailing edge of the blade near the hub surface. Such energy loss corresponds to the vortex LCS at the top of the impeller, and the two mirror each other.

This study focuses on the CFD numerical simulation and analysis of the vortex stacking problem at the top of the impeller of a high-speed fuel pump, mainly using LCS and entropy production theory to visualize the vortex at the top of the impeller as well as quantitatively analyzing the energy loss caused by the vortex at the top of the impeller. By combining the two methods, the two are well verified with each other that the stacking problem of the vortex at the top of the impeller and the location of the energy loss caused by the vortex are consistent with the vortex location. Such a method can reveal the problem of vortex buildup at the top of the lobe well, and provide a novel guidance idea for improving the performance of high-speed fuel pumps.

The purpose of this research is to examine the relationship between coaching leadership and employees' taking charge while incorporating the mediating role of work meaningfulness and the moderating role of challenge-hindrance stressor.

A total of 355 pairs of effective samples were collected through a two-stage supervisor-subordinate paired survey. Four hypotheses were tested using hierarchal regression analysis and bootstrapping method.

The findings show that coaching leadership is positively related to taking charge, and work meaningfulness positively mediates the coaching leadership-taking charge relationship; high challenge stressors and high hindrance stressors weaken the positive effect of coaching leadership on work meaningfulness respectively; challenge stressors and hindrance stressors further moderate the indirect relationship of coaching leadership and taking charge through work meaningfulness.

This study provides a new perspective for organizations to activate employees' taking charge, thereby enriching the antecedents of taking charge. By incorporating challenge-hindrance stressor framework, this study also provides answers to when coaching leadership will be less effective.

This study aims to investigate the impact of sustainable innovation and disruptive innovation on sustainable supply chain performance of manufacturing firms in Malaysia. The study also examined the moderating role of supply chain clockspeed in the relationship between sustainable innovation, disruptive innovation and sustainable supply chain performance.

The data were collected from 231 respondents in manufacturing firms in Malaysia. The data were analyzed using the partial least square-based structural equation modelling (PLS-SEM) technique.

The findings revealed that sustainable innovation and disruptive innovation had a significant and positive effect on sustainable supply chain performance. Supply chain clockspeed moderated the relationship between sustainable innovation and sustainable supply chain performance. The findings also identified that there was no moderating effect on the relationship between disruptive innovation and sustainable supply chain performance.

This study merely focuses on sustainable supply chain performance in Malaysian manufacturing firms. Samples from manufacturing firms in Malaysia were used in the current study, and the outcomes may vary for different nations.

To increase the firm’s commercial success, it is necessary to promote sustainable supply chain practices, including supply chain clockspeed, sustainable innovation and disruptive innovation.

This study adds to the body of knowledge by explaining the positive influence of sustainable innovation and disruptive innovation on sustainable supply chain performance in Malaysian manufacturing firms while also emphasizing the moderating role of supply chain clockspeed in this relationship. The contribution of this study could enable managers to develop sustainable supply chain performance in the manufacturing sector, based on sustainable innovation, disruptive innovation and supply chain clockspeed.

This study examines the impact of environmental activity management (EAM) on triple bottom line (TBL) performance and the role that sustainability strategies play in mediating these relationships. Data were collected using a survey of Australian managers and analysed using structural equation modelling (SEM). The findings indicate that each of the three levels of EAM – Environmental Activity Analysis, Environmental Activity Cost Analysis, and Environmental Activity Based Costing – influence-specific aspects of performance, either directly and/or indirectly through environmental and social sustainability strategies. The findings suggest that managers could enhance their use of EAM practices through the use of sustainability strategies in order to enhance performance. This study provides empirical insight into the impact that EAM practices and environmental and social sustainability strategies have on all three aspects of TBL performance.

Does the history of the bureaucratic system, along with the establishment of the Great Wall during the Ming and Qing dynasties (1368–1911), affect firm behavior across the borderlands of the Great Wall?

The Ming and Qing dynasties built a centralized administrative system in the borderlands on the south side of the Great Wall, in contrast to the “feudal lordship” system on the north side. Employing a regression discontinuity analysis framework with the Great Wall as a geographical discontinuity, we examine the long-run effects of the Great Wall on firms’ earnings management.

Using a large sample of nonlisted firms in the central core frontier region, we show that the earnings management of firms in the region south of the Great Wall is significantly curtailed compared with firms in the north of it, and this effect is more pronounced for non-SOEs. Our findings are robust to a battery of tests to account for alternative explanations.

Overall, by emphasizing the role of institutions, like legal system, shaped in history on firms’ earnings management, this study sheds new light on institutional determinants of firms’ behaviors in earnings information disclosure.

First, we enrich our understanding of the institutional determinants of firms’ financial reporting outcomes. Second, our findings shed new light on the long-term effects of historical ruling styles on modern corporate behavior.

The study of house prices has become more relevant in recent times after the global financial crisis. Using a housing data set from three regions of Ghana (collated from real estate agents), the purpose of this paper is to estimate the relative importance of housing attributes to house prices.

The hedonic regression analysis conducted indicates that location is the most powerful determinant of house prices. Other relevant factors are the number of bedrooms, the number of floors, the total floor area, land size, age of the house and luxury finishing.

The implications of these results are many. Policy wise, the study provides an evidence-based empirical study that supports the need for better urban planning to improve communities, which in turn is associated with house price appreciations. Homeowners, investors and creditors, particularly mortgage lenders could be the immediate beneficiaries. Drawing on this, improved urban planning could mitigate strategic defaults that results from house prices falling below mortgage loan balances. This is important for financial market stability.

The paper provides a comprehensive and unique understanding of the hedonic determinants of house prices in Ghana. Future studies could examine the effect of location upon mortgage lending in Ghana.

China has become an economic powerhouse in historic terms but there are a number of challenges to its continued prosperity. The aim of this paper is to more fully understand China's propensity for creative innovation, which is seen as an important next stage in its continued development.

The paper is conceptual but uses historical and secondary data to support its assumptions. The paper was written in conjunction with the 1st Global Peter F. Drucker Forum (celebrating 100 years since his birth) and attempts to continue his challenge of “the hard work of thinking”.

China has a long history of successful innovation. However, Confucian belief, a single despot and a closing off to the rest of the world have thwarted its innovative edge. The key to rekindling the entrepreneurial spirit is seen largely as an internal battle based on the state's ability to balance the institution of government with the needs of a burgeoning prospective creative class. This paper identifies that much of this change will rely on quality‐related developments rather than simply investments of financial capital.

The ability to create new things is a challenge to developing economies that rely on low cost and imitation. China's success in innovation will have substantial implications for developed nations both economically and geo‐politically. China wants to be a significant player on a global scale and this paper sheds light on its potential to achieve such an objective. Through traversing China's innovative landscape, this paper also enlightens the field of management on key aspects of China's innovative past, present and future.

The high-pressure accumulator has been widely used in the hydraulic system. Failure pressure prediction is crucial for the safe design and integrity assessment of the accumulators. The purpose of this study is to accurately predict the burst pressure and location for the accumulator shells due to internal pressure.

This study concentrates the non-linear finite element simulation procedure, which allows determination of the burst pressure and crack location using extensive plastic straining criterion. Meanwhile, the full-scale hydraulic burst test and the analytical solution are conducted for comparative analysis.

A good agreement between predicted and measured the burst pressure that was obtained, and the predicted failure point coincided very well with the fracture location of the actual shell very well. Meanwhile, the burst pressure of the shells increases with wall thickness, independent of the length. It can be said that the non-linear finite element method can be employed to predict the failure behavior of a cylindrical shell with sufficient accuracy.

This paper can provide a designer with additional insight into how the pressurized hollow cylinder might fail, and the failure pressure has been predicted accurately with a minimum error below 1%, comparing the numerical results with experimental data.