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Yinhai Zhu

Bio: Yinhai Zhu is an academic researcher from Tsinghua University. The author has contributed to research in topics: Injector & Heat transfer. The author has an hindex of 23, co-authored 62 publications receiving 1758 citations. Previous affiliations of Yinhai Zhu include Xi'an Jiaotong University & Nanyang Technological University.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the effects of two important ejector geometry parameters, the primary Nozzle Exit Position (NXP) and the mixing section converging angle θ, on its performance were investigated.

262 citations

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TL;DR: In this paper, a 2D exponential expression for velocity distribution is adopted to approximate the viscosity flow near the ejector inner wall to predict the performance of critical mode operation ejectors.

177 citations

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TL;DR: In this paper, the authors present a comprehensive literature review on three active cooling methods, i.e., regenerative cooling, film cooling, and transpiration cooling, including the fluids flow, heat transfer, and thermal cracking characteristics of different hydrocarbon fuels.

148 citations

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TL;DR: In this paper, an electrically heated vertical tube (2 mm inner diameter) was applied to carry out thermal cracking of supercritical pressure n-decane at various pressures, temperatures, and resident times.
Abstract: The flow and heat-transfer behavior of thermal cracking n-decane was investigated experimentally and numerically. An electrically heated vertical tube (2 mm inner diameter) was applied to carry out thermal cracking of supercritical pressure n-decane at various pressures, temperatures, and resident times. The results showed that the second-order reactions increase the formation rates of the light products (especially CH4 and C2H4) for conversions greater than 13%, while the heavy product (C5–C9) formation rates are decreased. A global reaction model is given for n-decane conversions less than 13%, including 18 main product species. A computational fluid dynamics (CFD) model was developed using the real thermal properties and coupled with fuel flow, heat transfer, and wall thermal conduction. Three turbulence models were tried out and then compared to the experimental results. The “SST k–ω model” can better predict the wall temperature than other turbulence models. The predicted fuel and wall temperatures a...

148 citations

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TL;DR: In this paper, the entrainment performance and the shock wave structures in a three-dimensional ejector were investigated by Computational Fluid Dynamics (CFD) and Schlieren flow visualization.
Abstract: The entrainment performance and the shock wave structures in a three-dimensional ejector were investigated by Computational Fluid Dynamics (CFD) and Schlieren flow visualization. The ejector performance was evaluated based on the mass flow rates of the primary and secondary flows. The shock wave structures in the ejector mixing chamber were captured by the optical Schlieren measurements. The results show that the expansion waves in the shock train do not reach the mixing chamber wall when the ejector is working at the sub-critical mode. Decreasing of the shock wave wavelength increases the secondary mass flow rate. A three-dimensional CFD model with four turbulence models was then compared with the experimental data. The results show that the RNG k - e model agrees best with measurements for predictions of both the mass flow rate and shock wave structures.

117 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a comprehensive literature review on ejector refrigeration systems and working fluids is presented, which deeply analyzes ejector technology and behavior, refrigerant properties and their influence over ejector performance.
Abstract: The increasing need for thermal comfort has led to a rapid increase in the use of cooling systems and, consequently, electricity demand for air-conditioning systems in buildings. Heat-driven ejector refrigeration systems appear to be a promising alternative to the traditional compressor-based refrigeration technologies for energy consumption reduction. This paper presents a comprehensive literature review on ejector refrigeration systems and working fluids. It deeply analyzes ejector technology and behavior, refrigerant properties and their influence over ejector performance and all of the ejector refrigeration technologies, with a focus on past, present and future trends. The review is structured in four parts. In the first part, ejector technology is described. In the second part, a detailed description of the refrigerant properties and their influence over ejector performance is presented. In the third part, a review focused on the main jet refrigeration cycles is proposed, and the ejector refrigeration systems are reported and categorized. Finally, an overview over all ejector technologies, the relationship among the working fluids and the ejector performance, with a focus on past, present and future trends, is presented.

359 citations

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TL;DR: In this paper, the authors investigated and reviewed the different technologies and approaches, and demonstrated their ability to improve the performance of HVAC systems in order to reduce energy consumption, and the influence of that method on the energy saving is investigated.

344 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of two important ejector geometry parameters, the primary Nozzle Exit Position (NXP) and the mixing section converging angle θ, on its performance were investigated.

262 citations

Journal ArticleDOI
TL;DR: A review of various researches of the mathematical model on the hydrodynamic and thermodynamic character within the ejector can be found in this paper, where various models consisting of ideal assumptions, governing equations, auxiliary conditions, solution methods and main results are presented.
Abstract: In ejector refrigeration systems, the performance of the ejector is critical to the performance, capability, size and cost of the whole system. Construction of mathematical models has been used as an effective method for analyzing the performance of the ejector as well as the whole refrigeration system. These models can also be used to guide system operation, interpret experimental results and assist in system design and optimization. The overall objective of this paper is to provide a review of various researches of the mathematical model on the hydrodynamic and thermodynamic character within the ejector. The paper first briefly describes ejector including fundamental principle, flowing and mixing mechanism and the method of model establishment. Then various models consisting of ideal assumptions, governing equations, auxiliary conditions, solution methods and main results are presented. The models can be classified into two main categories: (i) steady thermodynamic models which can be further subdivided into single-phase flow model and two-phase flow model and (ii) dynamic models which are also subdivided according to the flowing phases considered. It has been shown that the dynamic models have higher prediction precision and give more information compared with the steady thermodynamic models. In addition, the simplified empirical and semi-empirical models based on measured data are briefly discussed. This review is useful for understanding the evolution process and the current status of the mathematical models on ejector and highlighting the key aspects of model improvement such as the mixing mechanism, the capture of the shock wave, etc.

223 citations

Journal ArticleDOI
TL;DR: The objective of this work is to provide a literature survey on the research attempts made in the field of ejector refrigeration systems and the studies made on the ejector as a component.

202 citations