ASCA Observations of the Abell 496 Cluster of Galaxies

The metal in the intracluster medium (ICM) has been ejected or stripped from galaxies. Thus measurements of the metal distribution and the relative abundance of elements, in particular Si/Fe, are important to study the evolution of galaxies, as well as to study the chemical evolution of the ICM. We present the results from ASCA observations of Abell 496 cluster of galaxies. A496 is a nearby rich cluster with a central cD galaxy. At the redshift z=0.0327 of A496, 1 arcmin is 53kpc, where we assumed H0 = 50kms−1Mpc−1, q0 = 0.5. A496 is known as a cooling flow cluster. Edge and Stewart (1991) obtained the mass flow rate of and the cooling radius of 177 ± 52kpc.

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Effects of Slot Bleed Injection Over a Contoured Endwall on Nozzle Guide Vane Cooling Performance: Part I — Flow Field Measurements

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/2000-gt-0199 ◽

2000 ◽

Cited By ~ 36

Author(s):

Steven W. Burd ◽

Terrence W. Simon

Keyword(s):

Flow Field ◽

Secondary Flow ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Large Scale ◽

Secondary Flows ◽

Cooling Flow ◽

Nozzle Guide ◽

Aerodynamic Losses

Film cooling and secondary flows are major contributors to aerodynamic losses in turbine passages. This is particularly true in low aspect ratio nozzle guide vanes where secondary flows can occupy a large portion of the passage flow field. To reduce losses, advanced cooling concepts and secondary flow control techniques must be considered. To this end, combustor bleed cooling flows introduced through an inclined slot upstream of the airfoils in a nozzle passage were experimentally investigated. Testing was performed in a large-scale, high-pressure turbine nozzle cascade comprised of three airfoils between one contoured and one flat endwall. Flow was delivered to this cascade with high-level (∼9%), large-scale turbulence at a Reynolds number based on inlet velocity and true chord length of 350,000. Combustor bleed cooling flow was injected through the contoured endwall upstream of the contouring at bleed-to-core mass flow rate ratios ranging from 0 to 6%. Measurements with triple-sensor, hot-film anemometry characterize the flow field distributions within the cascade. Total and static pressure measurements document aerodynamic losses. The influences of bleed mass flow rate on flow field mean streamwise and cross-stream velocities, turbulence distributions, and aerodynamic losses are discussed. Secondary flow features are also described through these measurements. Notably, this study shows that combustor bleed cooling flow imposes no aerodynamic penalty. This is atypical of schemes where coolant is introduced within the passage for the purpose of endwall cooling. Also, instead of being adversely affected by secondary flows, this type of cooling is able to reduce secondary flow effects.

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Evaluate the Cooling Performance of Transmit/Receive Module Cooling System in Active Electronically Scanned Array Radar

Electronics ◽

10.3390/electronics10091044 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1044

Author(s):

Jun Su Park ◽

Dong-Jun Shin ◽

Sung-Hwan Yim ◽

Sang-Hyun Kim

Keyword(s):

Laminar Flow ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Cooling System ◽

Cooling Performance ◽

Cooling Flow ◽

Fluid Analysis ◽

Design Requirements

The active electronically scanned array (AESA) radar consists of many transmit/receive (T/R) modules and is used to track missiles approaching destroyers and fighters. The performance of the AESA radar depends on the T/R module temperature. The T/R module temperature should be maintained under 80 °C to guarantee the performance of the AESA radar. In order to match the design requirements of the cooling system of the AESA radar, it is necessary to evaluate the cooling performance according to various operation/installation environments. In this study, computational fluid analysis was performed by changing the number of T/R modules and the coolant mass flow rate to evaluate the cooling performance of the AESA radar coolant channel. The number of T/R modules was changed from 2 to 16, and the number of coolant inlet Re was changed from 277 to 11,116. As a result, it was confirmed that the temperature increased as the number of T/R modules increased. In addition, when the coolant status was laminar flow, it was confirmed that the cooling performance was significantly lowered. Therefore, the coolant status should be transient or turbulence to decrease the temperature of the T/R module. Additionally, the correlation between the arrangement of the T/R module and the cooling flow must be considered to cool the AESA radar.

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