ORCID Profile
0000-0003-3011-1599
Current Organisations
Commissariat à l’énergie atomique et aux énergies alternatives Direction CEA Tech
,
UNSW Sydney
,
Macquarie University
,
UNSW Australia
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Related Links
Publications
Computational Study of Wet Steam Flow to Optimize Steam Ejector Efficiency for Potential Fire Suppression Application
Publisher: MDPI AG
Date: 09-04-2019
DOI: 10.3390/APP9071486
Abstract: The steam ejector is a core component of an ejector-based refrigeration system. Additionally, steam ejectors can also be potentially applied for a fire suppression system by using pressurized steam droplets to rapidly quench and extinguish the fire. The use of steam will significantly reduce the amount of water consumption and pipe flow rate compared to conventional sprinklers. However, the efficiency of the steam ejector nozzle is one of major factors that can influence the extinguishing mechanisms and the performance of pressurized steam for fire suppression. In this article, to formulate an assessment tool for studying the ideal entrainment ratio and initial flow wetness, a wet steam model has been proposed to enhance our understanding of the condensation and evaporation effects of water droplets from a numerical perspective. The entire steam-ejector system including the nozzle, mixing chamber, throat and diffuser were modeled to study the profiles in axial pressure and temperature across the system, and were compared with self-measured experimental data. In addition, the flow and heat transfer interactions between the fluid mixture and nucleating water droplets were numerically examined by comparing initial conditions with different liquid fractions, as opposed to the ideal gas assumption. With the application of the proposed wet-steam model, the numerical model showed vast improvement in the axial pressure distribution over the ideal gas model. Through numerical conditions, it was found that reducing the wetness of the secondary inlet flow will potentially optimize the system performance with a significant increase of the entrainment ratio from 0.38 to 0.47 (i.e., improvement of around 23%).
A Large-Eddy Simulation study on the effect of fuel configuration and pan distance towards chemical species for under-ventilated compartment fire scenario
Publisher: Elsevier BV
Date: 03-2022
Experimental and numerical analysis of low-density gas dispersion characteristics in semi-confined environments
Publisher: Elsevier BV
Date: 12-2023
In-Depth Assessment of Cross-Passage Critical Velocity for Smoke Control in Large-Scale Railway Tunnel Fires
Publisher: MDPI AG
Date: 20-09-2022
DOI: 10.3390/FIRE5050140
Abstract: Demand for underground railways has rapidly increased due to accelerated urbanisation and population growth. This has elevated the importance of tunnel designs with adequate fire safety and protection measures. However, due to intricate modern rail tunnel designs, prescriptive codes are often difficult to implement and lead to over-conservative design. In this study, the current state of tunnel fire analysis was reviewed with a focus on Australia. A large-eddy simulation (LES)-based fire model was applied to investigate the temperature and smoke dispersion from a 2 MW metro tunnel fire case scenario to the cross-passage. A total of 28 cases with various cross-passage ventilation settings were examined, including longitudinal tunnel velocity, cross-passage velocity, train location relative to the cross-passage and fire location. The modelling showed that a 0.84 m/s critical velocity was sufficient for smoke control in the cross-passage. Furthermore, two empirical methods for cross-passage critical velocity were performed, which showed utilisation of the Froude number produced a less conservative critical velocity (0.610 m/s) compared to the dimensionless method (0.734 m/s). Nevertheless, both numerical and empirical results were significantly lower than the standard 1.0 m/s minimum flow rate for smoke control (AS1668.1). The results provide preliminary evidence towards the need for revision of current tunnel fire standards and response protocols.
Multiphase CFD modelling for enclosure fires—A review on past studies and future perspectives
Publisher: Springer Science and Business Media LLC
Date: 31-08-2022
On the Large Eddy Simulation Modelling of Water Suppression Systems Droplet Impact and Coverage Area
Publisher: MDPI AG
Date: 13-10-2022
DOI: 10.3390/FIRE5050165
Abstract: In this article, a collective database from validated numerical simulation has been established to study the suppression effects of water-based suppression systems under a single-compartment fire scenario at various suppression configurations and fire locations. Five fuel locations along the axis between the centre and corner of the room were configurated to dynamically analyse how the horizontal distance between the nozzle and fuel pan affects the heat release rate (HRR), temperature cooling phenomena at different heights and also the velocity profile. Throughout the fuel pan relocations, the water-mist system has achieved an average suppression time of 25 s for all the locations, it was found that the water mist system can effectively control the fire under 200 °C that is distanced over 2 m spanwise displacement from the nozzle against the fire, while the sprinkler has exhibited an excellent fuel surface cooling effect due to large momentum and heat capacity within the coverage area with an average suppression time of 50 s. The results of this study have further explored the spray coverage and droplet penetrability of different suppression systems at different locations corresponding to the fire source, and the quantitative assessment of fuel locations could also contribute to the future development of performance-based fire safety designs.
A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 1. Characterization of the Internal Flow Structure
Publisher: MDPI AG
Date: 12-10-2019
DOI: 10.3390/APP9204275
Abstract: With the escalating production of automobiles, energy efficiency and environmental friendliness have always been a major concern in the automotive industry. In order to effectively lower the energy consumption of a vehicle, it is essential to develop air-conditioning systems that can make good use of combustion waste heat. Ejector refrigeration systems have become increasingly popular for this purpose due to their energy efficiency and ability to recycle waste heat. In this article, the elements affecting the performance of a typical ejector refrigeration system have been explored using both experimental and numerical approaches. For the first time, the internal flow structure was characterized by means of comprehensive numerical simulations. In essence, three major sections of the steam ejector were investigated. Two energy processes and the shock-mixing layer were defined and analyzed. The results indicated that the length of the choking zone directly affects the entertainment ratio under different primary fluid temperature. The optimum enterainment ratio was achieved with 138 °C primary fluid temperature. The shock-mixing layer was greatly affected by secondary fluid temperature. With increasing of back pressure, the normal shock gradually shifted from the diffuser towards the throat, while the shock train length remains lunchanged.
A novel stochastic approach to study water droplet/flame interaction of water mist systems
Publisher: Informa UK Limited
Date: 27-01-2021
A novel thermal management system for battery packs in hybrid electrical vehicles utilising waste heat recovery
Publisher: Elsevier BV
Date: 10-2022
Numerical investigation of expandable graphite suppression on metal-based fire
Publisher: Springer Science and Business Media LLC
Date: 19-06-2021
Machine learning assisted advanced battery thermal management system: A state-of-the-art review
Publisher: Elsevier BV
Date: 04-2023
Application of multi-parametric characterization to water-based fire suppression systems in compartment fire scenarios
Publisher: Informa UK Limited
Date: 26-07-2022
A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 2. Understanding the Nature of the Shock Wave Structure
Publisher: MDPI AG
Date: 19-10-2019
DOI: 10.3390/APP9204435
Abstract: In general, engine fuel combustion generates 30% waste heat, which is disposed to the environment. The use of the steam ejector refrigeration to recycle the waste heat and transfer them to useful energy source could be an environmentally friendly solution to such an issue. The steam ejector is the main component of the ejector refrigeration system, which can operate at a low-temperature range. In this article, the internal shock wave structure of the ejector is comprehensively studied through the computation fluid dynamics (CFD) approach. The shock wave structure can be sub ided into two regions: firstly the pseudo-shock region consisting of shock train and co-velocity region secondly the oblique-shock region composed of a single normal shock and a series of oblique shocks. The effect of the shock wave structure on both pumping performance and the critical back pressure were investigated. Numerical predictions indicated that the entrainment ratio is enhanced under two conditions including (i) a longer pseudo-shock region and (ii) when the normal shock wave occurs near the outlet. Furthermore, the system is stabilized as the back pressure and its disturbance is reduced. A critical range of the primary fluid pressure is investigated such that the pumping is effectively optimized.
Flexible transparent conductive materials based on silver nanowire networks: a review
Publisher: IOP Publishing
Date: 11-10-2013
DOI: 10.1088/0957-4484/24/45/452001
Abstract: The class of materials combining high electrical or thermal conductivity, optical transparency and flexibility is crucial for the development of many future electronic and optoelectronic devices. Silver nanowire networks show very promising results and represent a viable alternative to the commonly used, scarce and brittle indium tin oxide. The science and technology research of such networks are reviewed to provide a better understanding of the physical and chemical properties of this nanowire-based material while opening attractive new applications.
Developing a solid decomposition kinetics extraction framework for detailed chemistry pyrolysis and combustion modelling of building polymer composites
Publisher: Elsevier BV
Date: 05-2022
Numerical modeling of wet steam infused fluid mixture for potential fire suppression applications
Publisher: Springer Science and Business Media LLC
Date: 14-06-2021
Numerical assessment of LES subgrid-scale turbulence models for expandable particles in fire suppression
Publisher: Springer Science and Business Media LLC
Date: 23-07-2023
Critical assessment on operating water droplet sizes for fire sprinkler and water mist systems
Publisher: Elsevier BV
Date: 03-2020
Evaluating the fire risk associated with cladding panels: An overview of fire incidents, policies, and future perspective in fire standards
Publisher: Wiley
Date: 08-04-2021
DOI: 10.1002/FAM.2973
Abstract: Multifunctional building façades have become an increasingly critical component in modern buildings, especially after the tremendous scrutiny triggered by the utilization of combustible aluminum cladding panels (ACP) in the construction sector. Following the massive effort by both industry and government agencies to reduce the fire risks of combustible façades in recent years, façades with insufficient fire ratings have been continuously causing severe building fires leading to countless human casualties and properties damages. This review aims to provide an in‐depth overview of the previous developments and current progress for establishing relevant fire standards with regards to ACPs, from an Australian standpoint. The fire spread mechanisms associate with ACPs, and their potential hazards were discussed. Furthermore, the current building regulations for ACPs have been reviewed, including detailed experimental procedures and rating criterion for all existing international standards. To address the research knowledge gap in terms of the understanding of the cladding fire mechanisms, and combustibility of existing ACP polymer composites, recent advancement in experimental and numerical studies has been summarized and discussed to identify the critical issues and concerns for current ACP products. Future perspectives involving cutting‐edge approaches such as computational fluid dynamics (CFD) modeling coupled with artificial neural network (ANN) optimization are advocated in this article. Additionally, fundamental material characterization techniques using molecular dynamics (MD) approaches can be implemented to deliver a better description of the degradation kinetics and smoke/toxicity generations.
Related Organisations
Commissariat À L’énergie Atomique Et Aux Énergies Alternatives Direction CEA Tech
Location: France
Related Funding Activities
No related grants have been discovered for Hengrui Liu.