Steam blow target plate configuration

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

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Experimental Study on Racetrack-Shaped Holes Impingement Cooling With Bump Type Roughening Element

Volume 4: Heat Transfer, Parts A and B ◽

10.1115/gt2012-69077 ◽

2012 ◽

Cited By ~ 1

Author(s):

Chiyuki Nakamata ◽

Yoji Okita ◽

Takashi Yamane ◽

Yoshitaka Fukuyama ◽

Toyoaki Yoshida

Keyword(s):

Experimental Study ◽

Flow Condition ◽

Reynolds Numbers ◽

Main Flow ◽

The Other ◽

Relative Location ◽

Target Plate ◽

Cooling Effectiveness ◽

Impingement Cooling ◽

Cooling Air

Cooling effectiveness of an impingement cooling with array of racetrack-shaped impingement holes is investigated. Two types of specimens are investigated. One is a plain target plate and the other is a plate roughened with bump type elements. Sensitivity of relative location of bump to impingement hole on the cooling effectiveness is also investigated. Experiments are conducted under three different mainflow Reynolds numbers ranging from 2.6×105 to 4.7×105, with four different cooling air Reynolds numbers for each main flow condition. The cooling air Reynolds numbers are in the range from 1.2×103 to 1.3×104.

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Generation of longitudinal vortices in internal flows with an inclined impinging jet and enhancement of target plate heat transfer

International Journal of Heat and Fluid Flow ◽

10.1016/s0142-727x(98)10019-x ◽

1998 ◽

Vol 19 (5) ◽

pp. 573-581 ◽

Cited By ~ 10

Author(s):

K Nakabe ◽

K Suzuki ◽

K Inaoka ◽

A Higashio ◽

J.S Acton ◽

...

Keyword(s):

Heat Transfer ◽

Impinging Jet ◽

Internal Flows ◽

Target Plate ◽

Plate Heat ◽

Longitudinal Vortices

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Experimental Study of Multiple Air Jets Impinging a Moving Flat Plate

Volume 11: Heat Transfer and Thermal Engineering ◽

10.1115/imece2020-23996 ◽

2020 ◽

Author(s):

Flavia Barbosa ◽

Senhorinha Teixeira ◽

Carlos Costa ◽

Filipe Marques ◽

José Carlos Teixeira

Keyword(s):

Heat Transfer ◽

Flat Plate ◽

Jet Impingement ◽

Plate Motion ◽

Test Facility ◽

Flat Plates ◽

Target Plate ◽

Wall Jets ◽

Air Jets ◽

Flow Interactions

Abstract The motion of the target plate is important in some industrial applications which apply multiple jet impingement, such as reflow soldering, drying and food processing. Multiple jet impingement is widely used due to its ability to generate high heat transfer rates over large and complex areas. This convective process is characterized by several flow interactions essentially due to adjacent jets mixing prior the impingement, wall jets collision after the impingement, as well as crossflow interactions induced by the motion of the wall jets that flow through the exits of the domain. These interactions lead to strong flow recirculation, pressure gradients and boundary layer development. However, the complexity of the flow interactions is increased with the surface motion in confined space, due to the generation of strong shear regions. These interactions can induce problems and product defects due to complicated thermal behavior and non-uniform heating or cooling, being important to fully understand the process in order to reduce time and costs. This work addresses the experimental analysis of multiple air jets impinging on a moving flat plate. The experiments are conducted on a purpose-built test facility which has been commissioned, using a 2D-PIV system. Through this technique, the flow structure and velocity profiles will be analyzed in detail. The effects of the impinging plate motion on the resulting global and local velocity profile is compared with a static flat plate. The multiple jet configuration consists on air flowing through 14 circular nozzles, at a Reynolds number of 690 and 1,380. The experiments are conducted for a nozzle-to-plate distance of 8 and a jet-to-jet spacing of 2. The target plate motion remains constant throughout the experiments and equal to 0.03 m/s. The results are compared for both stationary and moving flat plates cases and express the increased complexity of the flow due to strong interaction between jets and the target surface, which affects the heat transfer performance. The results obtained experimentally are important to clearly define this complex flow and these data can be used in future works for numerical model validation.

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Effect of Jet-to-Jet Distance and Pipe Position on Flow and Heat Transfer Features of Active Clearance Control Systems

10.1115/gt2021-59158 ◽

2021 ◽

Author(s):

Lorenzo Cocchi ◽

Alessio Picchi ◽

Bruno Facchini ◽

Riccardo Da Soghe ◽

Lorenzo Mazzei ◽

...

Keyword(s):

Heat Transfer ◽

Target Surface ◽

Reynolds Numbers ◽

Metal Plate ◽

Target Distance ◽

Target Plate ◽

Ir Camera ◽

Supply Pipe ◽

Heating Up ◽

Clearance Control

Abstract The goal of the present work is to investigate the effect of supply pipe position on the heat transfer features of various active clearance control (ACC) geometries, characterized by different jet-to-jet distances. All geometries present 0.8 mm circular impingement holes arranged in a single row. The jets generated by such holes cool a flat target surface, which is replicated by a metal plate in the experimental setup. Measurements are performed using the steady-state technique, obtained by heating up the target plate thanks to an electrically heated Inconel foil applied on the side of the target opposite to the jets. Temperature is also measured on this side by means of an IR camera. Heat transfer is then evaluated thanks to a custom designed finite difference procedure, capable of solving the inverse conduction problem on the target plate. The effect of pipe positioning is studied in terms of pipe-to-target distance (from 3 to 11 jet diameters) and pipe orientation (i.e. rotation around its axis, from 0° to 40° with respect to target normal direction), while the investigated jet Reynolds numbers range from 6000 to 10000. The obtained results reveal that heat transfer is maximized for a given pipe-to-target distance, dependent on both jet-to-jet distance and target surface extension. Pipe rotation also affects the cooling features in a non-monotonic way, suggesting the existence of different flow regimes related to jet inclination.

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A Lab-Scale Experiment Approach to the Measurement of Wall Pressure from Near-Field under Water Explosions by a Hopkinson Bar

Shock and Vibration ◽

10.1155/2018/8273469 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 4

Author(s):

Xiongwei Cui ◽

Xiongliang Yao ◽

Yingyu Chen

Keyword(s):

Shock Wave ◽

Near Field ◽

Underwater Explosion ◽

Experimental System ◽

Hopkinson Bar ◽

Wall Pressure ◽

Pressure Loading ◽

Target Plate ◽

Wave Pressure ◽

Shock Wave Pressure

Direct measurement of the wall pressure loading subjected to the near-field underwater explosion is of great difficulty. In this article, an improved methodology and a lab-scale experimental system are proposed and manufactured to assess the wall pressure loading. In the methodology, a Hopkinson bar (HPB), used as the sensing element, is inserted through the hole drilled on the target plate and the bar’s end face lies flush with the loaded face of the target plate to detect and record the pressure loading. Furthermore, two improvements have been made on this methodology to measure the wall pressure loading from a near-field underwater explosion. The first one is some waterproof units added to make it suitable for the underwater environment. The second one is a hard rubber cylinder placed at the distal end, and a pair of ropes taped on the HPB is used to pull the HPB against the cylinder hard to ensure the HPB’s end face flushes with loaded face of the target plate during the bubble collapse. To validate the pressure measurement technique based on the HPB, an underwater explosion between two parallelly mounted circular target plates is used as the validating system. Based on the assumption that the shock wave pressure profiles at the two points on the two plates which are symmetrical to each other about the middle plane of symmetry are the same, it was found that the pressure obtained by the HPB was in excellent agreement with pressure transducer measurements, thus validating the proposed technique. To verify the capability of this improved methodology and experimental system, a series of minicharge underwater explosion experiments are conducted. From the recorded pressure-time profiles coupled with the underwater explosion evolution images captured by the HSV camera, the shock wave pressure loading and bubble-jet pressure loadings are captured in detail at 5 mm, 10 mm, …, 30 mm stand-off distances. Part of the pressure loading of the experiment at 35 mm stand-off distance is recorded, which is still of great help and significance for engineers. Especially, the peak pressure of the shock wave is captured.

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Local Heat Transfer Coefficient and Adiabatic Wall Temperature Measurement Beneath Arrays of Staggered and Inline Impinging Jets

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/94-gt-181 ◽

1994 ◽

Cited By ~ 1

Author(s):

Kenneth W. Van Treuren ◽

Zuolan Wang ◽

Peter T. Ireland ◽

Terry V. Jones ◽

S. T. Kohler

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Wall Temperature ◽

Impinging Jets ◽

Hole Diameter ◽

Channel Height ◽

Published Data ◽

Target Plate ◽

Adiabatic Wall

Recent work, Van Treuren et al. (1993), has shown the transient method of measuring heat transfer under an array of impinging jets allows the determination of local values of adiabatic wall temperature and heat transfer coefficient over the complete surface of the target plate. Using this technique, an inline array of impinging jets has been tested over a range of average jet Reynolds numbers (10,000–40,000) and for three channel height to jet hole diameter ratios (1, 2, and 4). The array is confined on three sides and spent flow is allowed to exit in one direction. Local values are averaged and compared with previously published data in related geometries. The current data for a staggered array is compared to those from an inline array with the same hole diameter and pitch for an average jet Reynolds number of 10,000 and channel height to diameter ratio of one. A comparison is made between intensity and hue techniques for measuring stagnation point and local distributions of heat transfer. The influence of the temperature of the impingement plate through which the coolant gas flows on the target plate heat transfer has been quantified.

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