Qiuwang Wang, Feng Wu, Min Zeng, Laiqin Luo and Jiguo Sun
To find the optimal number of channels of rocket engine thrust chamber, it was found that the optimal channel number is 335, at which the cooling effect of the thrust chamber…
Abstract
Purpose
To find the optimal number of channels of rocket engine thrust chamber, it was found that the optimal channel number is 335, at which the cooling effect of the thrust chamber cooling channel reaches the best, which can be helpful to design rocket engine thrust chamber.
Design/methodology/approach
The commercial computational fluid dynamics (CFD) software FLUENT with standard k‐ε turbulent model was used. The CFD method was validated via comparing with the available experimental data.
Findings
It was found that both the highest temperature and the maximal heat flux through the wall on the hot‐gas side occurs about the throat region at the symmetrical center of the cooling channel. Owing to the strong curvature of the cooling channel geometry, the secondary flow reached its strongest level around the throat region. The typical values of pressure drop and temperature difference between the inlet and exit of cooling channel were 2.7 MPa and 67.38 K (standard case), respectively. Besides an optimal number of channels exist, and it is approximately 335, which can make the effect of heat transfer of cooling channels best with acceptable pressure drop. As a whole, the present study gives some useful information to the thermal design of liquid rocket engine thrust chamber.
Research limitations/implications
More detailed computation and optimization should be performed for the fluid flow and heat transfer of cooling channel.
Practical implications
A very useful optimization on heat transfer and fluid flow in cooling channel of liquid rocket engine thrust chamber.
Originality/value
This paper provides the performance of optimization on heat transfer and fluid flow in cooling channel of liquid rocket engine thrust chamber, which can make the effect of heat transfer of cooling channels best with acceptable pressure drop. As a whole, the present study gives some useful information to the thermal design of liquid rocket engine thrust chamber.
Details
Keywords
Abstract
Purpose
Little attention has been given to the effects of returnee entrepreneurs on external and internal corporate social responsibility (CSR). This study aims to investigate whether returnee entrepreneurs engage in more external or internal CSR and to further explore the contingency effects of foreign market embeddedness and local government endorsement.
Design/methodology/approach
This study uses 11,967 startups in China to examine the relationship between returnee entrepreneurs and external and internal CSR. The authors use an ordinary least square regression and propensity scoring matching approach to analyze the data.
Findings
The empirical results show that returnee entrepreneurs are more likely to undertake external CSR but less likely to undertake internal CSR. Foreign market embeddedness and local government endorsement have opposite moderating effects on these relationships.
Practical implications
This study has important implications for returnee entrepreneurs’ strategic choice between external and internal CSR and also provides theoretical support for policymakers to make effective and enforceable CSR policies.
Originality/value
This study discusses how returnee entrepreneurs implement external or internal CSR in China, answering the call to distinguish between external and internal CSR. Drawing on a legitimacy perspective, the authors find interesting and seemingly counterintuitive effects of returnees on external and internal CSR, which also necessitates distinguishing between these two types of CSR. In addition, the authors find different moderating roles of foreign market embeddedness and local government endorsement.