The radiative heat flux of the plume from reusable rockets is a critical parameter during the launch and return processes.This paper proposes a method for calculating radiative heat flux with higher accuracy than prev...The radiative heat flux of the plume from reusable rockets is a critical parameter during the launch and return processes.This paper proposes a method for calculating radiative heat flux with higher accuracy than previously reported for a recoverable nine-engine liquid-propellant rocket.Based on the Radiative Transfer Equation(RTE),this study employs the discrete transfer method to solve the transient RTE problem using physical properties to describe the problem while avoiding the need to directly solve mathematical equations.The proposed method can effectively determine the radiative heat flux of the flow field and is applicable to problems involving various geometries.Calculations reveal that during the ascent phase of the rocket,the radiative heat flux at the base of the vehicle reaches its maximum in the initial stages of the lift-off,reaching a maximum of~50 kW/m^(2),which is 2.24 times the maximum value during the return phase.During the deceleration stage of re-entry into the atmosphere,the maximum radiative heat flux recorded on the sidewall of the rocket is 29.1 kW/m^(2);the maximum heat flux on the bottom surface is approximately 22.3 kW/m^(2),accounting for 76.6%of that on the rocket's sidewall.This provides a basis for the thermal protection design of the rocket's bottom and walls as well as for the thermal management of cryogenic propellant tanks.Future research will involve ground engine testing and flight experiments to further validate the proposed model.展开更多
This article focuses on the development of the international service trade statistics system.The 1994 General Agreement on Trade in Services(GATS)provided a institutional basis for service trade statistics.The 2002“I...This article focuses on the development of the international service trade statistics system.The 1994 General Agreement on Trade in Services(GATS)provided a institutional basis for service trade statistics.The 2002“International Service Trade Statistics Manual”(MSITS 2002)established the international balance of payments statistics paradigm.The revised MSITS 2010 in 2010 introduced the expanded balance of payments service classification(EBOPS 2010),incorporating foreign affiliate service trade statistics(FATS),and constructing a comprehensive statistics system.The update of MSITS 2010 originated from changes in the global economic environment,technological progress leading to diversified forms of service trade,and the demands of international service trade negotiations.This standard has constructed a multi-level classification system.Since the release of MSITS 2010,many countries have implemented the new statistical framework,but some developing countries face challenges.International organizations and developed countries have provided corresponding support for service trade statistics standards.展开更多
文摘The radiative heat flux of the plume from reusable rockets is a critical parameter during the launch and return processes.This paper proposes a method for calculating radiative heat flux with higher accuracy than previously reported for a recoverable nine-engine liquid-propellant rocket.Based on the Radiative Transfer Equation(RTE),this study employs the discrete transfer method to solve the transient RTE problem using physical properties to describe the problem while avoiding the need to directly solve mathematical equations.The proposed method can effectively determine the radiative heat flux of the flow field and is applicable to problems involving various geometries.Calculations reveal that during the ascent phase of the rocket,the radiative heat flux at the base of the vehicle reaches its maximum in the initial stages of the lift-off,reaching a maximum of~50 kW/m^(2),which is 2.24 times the maximum value during the return phase.During the deceleration stage of re-entry into the atmosphere,the maximum radiative heat flux recorded on the sidewall of the rocket is 29.1 kW/m^(2);the maximum heat flux on the bottom surface is approximately 22.3 kW/m^(2),accounting for 76.6%of that on the rocket's sidewall.This provides a basis for the thermal protection design of the rocket's bottom and walls as well as for the thermal management of cryogenic propellant tanks.Future research will involve ground engine testing and flight experiments to further validate the proposed model.
基金The interim results of the postdoctoral research project“Research on the Evolution Process of Shenzhen’s High-tech Industry Policies(1980-2022)”(Project Number:6023271023S)at the end of the postdoctoral period of Shenzhen Polytechnic University.Institute of Economic and Social Development(Phase III)Project:6025310002Q.
文摘This article focuses on the development of the international service trade statistics system.The 1994 General Agreement on Trade in Services(GATS)provided a institutional basis for service trade statistics.The 2002“International Service Trade Statistics Manual”(MSITS 2002)established the international balance of payments statistics paradigm.The revised MSITS 2010 in 2010 introduced the expanded balance of payments service classification(EBOPS 2010),incorporating foreign affiliate service trade statistics(FATS),and constructing a comprehensive statistics system.The update of MSITS 2010 originated from changes in the global economic environment,technological progress leading to diversified forms of service trade,and the demands of international service trade negotiations.This standard has constructed a multi-level classification system.Since the release of MSITS 2010,many countries have implemented the new statistical framework,but some developing countries face challenges.International organizations and developed countries have provided corresponding support for service trade statistics standards.
