Temperature distribution of a test specimen with high-speed heat air-flow passing through

Xiong, Kai; Li, Yunhua; Dong, Sujun

doi:10.2298/tsci160302217x

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…The specific heat capacity C p , thermal conductivity λ, and dynamic viscosity µ, are calculated by fitting the function of temperature from 273 K to 2100 K, as shown in Formulas ( 9), ( 10), (11), and ( 12), respectively. Formulas ( 9)-( 12) represent physical property parameters of the combustion gas, which are obtained by fitting the data in reference [37]. For the simulation of subsonic combustion gas flow heating, a pressure-based solution method can be adopted, and numerical solutions can be achieved through the pressure/velocity correction relationship.…”

Section: Generation Of Stagnation Point Heat Flux By Cfd Numerical Si...mentioning

confidence: 99%

Study on Ground Experimental Method of Stagnation Point Large Heat Flux of Typical Sharp Wedge Leading Edge Structure

Wang,

Lou,

et al. 2023

Aerospace

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In this paper, aimed at the problem of large temperature gradient thermal testing with the typical sharp wedge leading edge structure of a hypersonic vehicle, a subsonic high-temperature combustion gas heating (SHCH) test device is used to conduct a series of experiments on the heat flux simulation ability of subsonic high-temperature combustion gas in the stagnation point region. Firstly, for a hypersonic vehicle with a flying height of 24 km and Mach number range of 4~6.5, the stagnation point heat flux in the head area is obtained by numerical calculation of a typical leading edge structure, which is used as the experimental target of the thermal structure test. Secondly, an experimental specimen with a Gardon heat flux meter is designed with the same shape and size as the specimen in the numerical simulations to prepare for the subsequent SHCH test. Thirdly, a method to determine the combustion gas temperature based on a Kriging surrogate model is proposed. CFD numerical simulation is conducted using the SHCH test model, and the numerical calculation results are used as the training dataset. The Kriging surrogate model is used to establish an approximate fitting relationship between the stagnation point heat flux and experimental parameters under SHCH conditions. The corresponding combustion gas temperature values are found, respectively, with the hypersonic aerodynamic heat flux at Mach 5.0~5.4 as the target value. Finally, stagnation point heat flux testing of low-speed and high-temperature combustion gas is performed at different combustion gas temperatures. The experimental and target values obtained from hypersonic aerodynamic thermal simulations are compared and analyzed to verify the heating capacity of SHCH and the feasibility of hypersonic aerothermal simulation testing.

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Section: Generation Of Stagnation Point Heat Flux By Cfd Numerical Si...mentioning

confidence: 99%

Study on Ground Experimental Method of Stagnation Point Large Heat Flux of Typical Sharp Wedge Leading Edge Structure

Wang,

Lou,

et al. 2023

Aerospace

Self Cite

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“…The windage loss in BLSG is produced from the friction between the rotating surface and the surrounding gas. Equation (A5) can be used to calculate the windage loss [ 46 , 49 , 50 ]: According to SKF (1994) [ 29 ], the bearing friction losses can be obtained by Equation (A6).

where

is the machine loss,

is the windage loss,

is the bearing fraction loss,

the is the friction coefficient,

is the density of the air in the BLSG,

is the rotating speed,

is the diameter of the rotor,

is the rotor core length,

is the friction coefficient (typically 0.001–0.005),

is the bearing load, and

is the inner diameter of the bearing.…”

Section: Figure A1mentioning

confidence: 99%

Numerical Investigation on the Thermal Performance of Nanofluid-Based Cooling System for Synchronous Generators

Xiong

et al. 2019

Entropy

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This paper presents a nanofluid-based cooling method for a brushless synchronous generator (BLSG) by using Al2O3 lubricating oil. In order to demonstrate the superiority of the nanofluid-based cooling method, analysis of the thermal performance and efficiency of the nanofluid-based cooling system (NBCS) for the BLSG is conducted along with the modeling and simulation cases arranged for NBCS. Compared with the results obtained under the base fluid cooling condition, results show that the nanofluid-based cooling method can reduce the steady-state temperature and power losses in BLSG and decrease the temperature settling time and changing ratio, which demonstrate that both steady-state and transient thermal performance of NBCS are improved as nanoparticle volume fraction (NVF) in nanofluid increases. Besides, although the input power of cycling pumps in NBCS has ~30% increase when the NVF is 10%, the efficiency of the NBCS has a slight increase because the 4.1% reduction in power loss of BLSG is bigger than the total incensement of input power of the cycling pumps. The results illustrate the superiority of the nanofluid-based cooling method, and it indicates that the proposed method has a broad application prospect in the field of thermal control of onboard synchronous generators with high power density.

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Optimisation Design of Thermal Test System for Metal Fibre Surface Combustion Structure

Qi,

Yang

et al. 2024

Aerospace

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The metal fibre surface combustion structure has the characteristics of strong thermal matching ability, short response time, and strong shape adaptability. It has more advantages in the thermal test of complex hypersonic vehicle surface inlet, leading edge, etc. In this paper, a method of aerodynamic thermal simulation test based on metal fibre surface combustion is proposed. The aim of the study was to create a uniform target heat flow on the inner wall surface of a cylindrical specimen by matching the gas jet flow rate and the geometry of the combustion surface. The research adopted the optimisation design method based on the surrogate model to establish the numerical calculation model of a metal fibre combustion jet heating cylinder specimen. One hundred sample points were obtained through Latin hypercube sampling, and a database of design parameters and heat flux was established through numerical simulation. The kriging surrogate model and the non-dominated sequencing genetic optimisation algorithm with elite strategy were adopted. A bi-objective optimisation design was carried out with the optimisation objective of the coincidence between the predicted and the target heat flux on the inner wall of the specimen. The results showed that the average relative errors of heat flow density on the specimen surface were 8.8% and 6% through the leave-one-out cross-validation strategy and the validation of six test sample points, respectively. The relative error values in most regions were within 5%, which indicates that the established kriging surrogate model has high prediction accuracy. Under the optimal solution conditions, the numerical calculation results of the heat flow on the inner wall of the specimen were in good agreement with the target heat flow values, with an average relative error of less than 5% and a maximum value of less than 8%. These results show that the optimisation design method based on the kriging surrogate model can effectively match the thermal test parameters of metal fibre combustion structures.

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Temperature distribution of a test specimen with high-speed heat air-flow passing through

Cited by 3 publications

References 27 publications

Study on Ground Experimental Method of Stagnation Point Large Heat Flux of Typical Sharp Wedge Leading Edge Structure

Study on Ground Experimental Method of Stagnation Point Large Heat Flux of Typical Sharp Wedge Leading Edge Structure

Numerical Investigation on the Thermal Performance of Nanofluid-Based Cooling System for Synchronous Generators

Optimisation Design of Thermal Test System for Metal Fibre Surface Combustion Structure

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