Convective Heat Transfer in Impinging- Gas- Jet Arrangements

The paper deals with heat transfer by convection between impinging gas jets and solid surfaces. It considers both single and multiple jet systems. It emphasizes the flow and geometrical parameters as well as the environment conditions at which the jet emerges. In particular, it points out the effect of the jet tilting, thermal entrainment and jet confinement. ASN and ARN schemes are illustrated through industrial and aeronautical applications. Design correlations are proposed. Experimental data obtained from infrared thermography are compared to CFD simulations

Convective Heat Transfer and Infrared Thermography (IRTh)

The paper deals with the application of the infrared thermography to the determination of the convective heat transfer coefficient in complex flow configurations. The fundamental principles upon which the IRTh relies are reviewed. The different methods developed to evaluate the heat exchange are described and illustrated through applications to the aerospace and aeronautical field as well as to the industrial processes

Image processing techniques for the characterization of explosively driven dispersions

PresentationDispersions driven by explosions are challenging to characterize mainly due to the extreme test conditions, the different time and spatial scales of the flow, and the variation of intensity due to the combustion. An intensity based optical method to characterize the dispersion driven by an explosion is proposed. The velocity and intensity maps of the dispersion are accessed through the post- processing of the images of the dispersion. These images can be obtained either from a global visualization (using a light source, such as in the image given in Figure 1, or the combustion light itself) or from a transversal visualization (using a laser sheet illuminating inside the cloud, such as in the image given in Figure 2). The developed method is organized into three steps. First, the contour of the cloud is detected via a dynamic grey-scale threshold criterion. The dispersion contours allow the computation of the velocity of the expansion as long as the plume presents a regular edge. Then, Large-Scale Particle Image Velocimetry technique is applied to obtain the velocity map of the dispersion. Additionally, information about the combustion phenomenon can also be accessed via an intensity-based analysis. The method has been initially verified using a numerical test case. It has been thereafter applied on different experimental measurements presenting challenging features such as variations of light intensity, time scales, and spatial scales

Experimental investigation of blast wave propagation in an urban environment

PresentationLab-scale experimental investigations on blast wave propagation in a complex environment are proposed in this paper. Studies of blast propagation are described in the literature, but only a few studies at lab-scale were found while this scale option represents an economic and safe approach. Five experimental configurations, built with wood boxes on a 2.8 m wood table, are tested in a 1:200 reduced scale using three types of explosives. Several characteristics of the explosives are given: the geometry of the explosion, the repeatability, and the TNT equivalent. An overview of impacts of a complex environment on the blast wave characteristics is proposed. The urban configurations investigated are the straight street, the T-junction, the cross junction, and the channeling. Investigations on reduced-scale effects on blast measurement and characteristics are detailed

Measurements Methods for the analysis of Nuclear Reactors Thermal Hydraulic in Water Scaled Facilities

The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast spectrum research reactor, conceived as an accelerator driven system (ADS). The configuration of the primary loop is pool-type: the primary coolant and all the primary system components (core and heat exchangers) are contained within the reactor vessel, while the secondary fluid is circulating in the heat exchangers. The primary coolant is Lead Bismuth Eutectic (LBE). The recent nuclear accident of Fukushima in 2011 changed the requirements for the design of new reactors, which should include the possibility to remove the residual decay heat through passive primary and secondary systems, i.e. natural convection (NC). After the reactor shut down, in the unlucky event of propeller failures, the primary and secondary loops should be able to remove the decay heat in passive way (Natural Convection). The present study analyses the flow and the temperature distribution in the upper plenum by applying laser imaging techniques in a laboratory scaled water model. A parametric study is proposed to study stratification mitigation strategies by varying the geometry of the buffer tank simulating the upper plenum

Reply by the authors to H. Wong's comment on "effect of nozzle cavity on resonance in large SRM : theoretical modelling"

No abstract

Measurements Methods for the analysis of Nuclear Reactors Thermal Hydraulic in Water Scaled Facilities

The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast spectrum research reactor, conceived as an accelerator driven system (ADS). The configuration of the primary loop is pool-type: the primary coolant and all the primary system components (core and heat exchangers) are contained within the reactor vessel, while the secondary fluid is circulating in the heat exchangers. The primary coolant is Lead Bismuth Eutectic (LBE). The recent nuclear accident of Fukushima in 2011 changed the requirements for the design of new reactors, which should include the possibility to remove the residual decay heat through passive primary and secondary systems, i.e. natural convection (NC). After the reactor shut down, in the unlucky event of propeller failures, the primary and secondary loops should be able to remove the decay heat in passive way (Natural Convection). The present study analyses the flow and the temperature distribution in the upper plenum by applying laser imaging techniques in a laboratory scaled water model. A parametric study is proposed to study stratification mitigation strategies by varying the geometry of the buffer tank simulating the upper plenum

Stratification mitigation in the upper tank of a natural circulation loop simulating passive decay heat removal in a pool type reactor

The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast spectrum research reactor , conceived as an accelerator driven system (ADS). The configuration of the primary loop is pool-type: the primary coolant and all the primary system components (core and heat exchangers) are contained within the reactor vessel, while the secondary fluid is circulating in the heat exchangers. The primary coolant is Lead Bismuth Eutectic (LBE). After the reactor shut down, in the unlucky event of propeller failures, the primary and secondary loops should be able to remove the decay heat in passive way (Natural Convection). The present study analyses the flow and the temperature distribution in the upper plenum by applying laser imaging techniques in a laboratory scaled water model. A parametric study is proposed to study stratification mitigation strategies by varying the geometry of the buffer tank simulating the upper plenum.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers