Simultaneous measurements of heat flow rate and thermal properties of nano boron trioxide under neutron irradiation at the low and high temperature

Vacuum ◽  
2020 ◽  
Vol 173 ◽  
pp. 109162 ◽  
Author(s):  
Matlab N. Mirzayev
Keyword(s):  
Thermal Properties ◽  
High Temperature ◽  
Heat Flow ◽  
Neutron Irradiation ◽  
Flow Rate ◽  
Heat Flow Rate ◽  
Boron Trioxide ◽  
Simultaneous Measurements

Heat and Mass Transfer to Air in a Cross Flow Heat Exchanger with Surface Deluge Cooling

2016 ◽  
Vol 24 (01) ◽  
pp. 1650002 ◽  
Author(s):  
Andrea Diani ◽  
Luisa Rossetto ◽  
Roberto Dall’Olio ◽  
Daniele De Zen ◽  
Filippo Masetto
Keyword(s):  
Heat Exchanger ◽  
Heat Flow ◽  
Flow Rate ◽  
Data Center ◽  
Heat Dissipation ◽  
Cross Flow ◽  
Critical Conditions ◽  
Heat Flow Rate ◽  
External Temperature ◽  
Flow Heat

Cross flow heat exchangers, when applied to cool data center rooms, use external air (process air) to cool the air stream coming from the data center room (primary air). However, an air–air heat exchanger is not enough to cope with extreme high heat loads in critical conditions (high external temperature). Therefore, water can be sprayed in the process air to increase the heat dissipation capability (wet mode). Water evaporates, and the heat flow rate is transferred to the process air as sensible and latent heat. This paper proposes an analytical approach to predict the behavior of a cross flow heat exchanger in wet mode. The theoretical results are then compared to experimental tests carried out on a real machine in wet mode conditions. Comparisons are given in terms of calculated versus experimental heat flow rate and evaporated water mass flow rate, showing a good match between theoretical and experimental values.

scholarly journals Performance of Air-Cooled Heat Exchanger with Laminar, Transitional, and Turbulent Tube Flow

2018 ◽  
Vol 240 ◽  
pp. 02012
Author(s):  
Dawid Taler
Keyword(s):  
Nusselt Number ◽  
Heat Exchanger ◽  
Heat Flow ◽  
Friction Factor ◽  
Flow Rate ◽  
Empirical Relationship ◽  
Heat Flow Rate ◽  
Transition Flow ◽  
Water Side ◽  
Wide Range

Some air-cooled heat exchangers, especially in air conditioning and heating installations, heat pumps, as well as car radiators, work in a wide range of loads when the liquid flow in the tubes can be laminar, transitional or turbulent. In this paper, a semi-empirical and empirical relationship for the Nusselt number on the liquid-side in the transitional and turbulent range was derived. The friction factor in the transition flow range Rew,trb ≤ Rew ≤ Rew,tre was calculated by linear interpolation between the values of the friction factor for Rew,trb =2,100 and Rew,tre =3,000. Based on experimental data for a car radiator, empirical heat transfer relationships for the air and water-side were found by using the least squares method. The water temperature at the outlet of the heat exchanger was calculated using P-NTU (effectiveness-number of transfer units) method. The heat flow rate from water to air was calculated as a function of the water flow rate to compare it with the experimental results. The theoretical and empirical correlation for the water-side Nusselt number developed in the paper were used when determining the heat flow rate. The calculation results agree very well with the results of the measurements.

scholarly journals MODEL OF HEAT SIMULATOR FOR DATA CENTERS

2016 ◽  
Vol 56 (4) ◽  
pp. 301-305
Author(s):  
Jan Novotný ◽  
Jiří Nožička
Keyword(s):  
Temperature Field ◽  
Heat Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Data Centers ◽  
Heat Output ◽  
Heat Flow Rate ◽  
Flow Rates ◽  
Piv Method ◽  
Mass Flow Rates

The aim of this paper is to present a design and a development of a heat simulator, which will be used for a flow research in data centers. The designed heat simulator is based on an ideological basis of four-processor 1U Supermicro server. The designed heat simulator enables to control the flow and heat output within the range of 10–100 %. The paper covers also the results of testing measurements of mass flow rates and heat flow rates in the simulator. The flow field at the outlet of the server was measured by the stereo PIV method. The heat flow rate was determined, based on measuring the temperature field at the inlet and outlet of the simulator and known mass flow rate.

scholarly journals Possible interrelation between the lead time of precursory seismic electric signals (SES) and geodynamics in Aegean Sea

2011 ◽  
Vol 11 (6) ◽  
pp. 1599-1603 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Heat Flow ◽  
Flow Rate ◽  
Lead Time ◽  
Aegean Sea ◽  
High Heat ◽  
Heat Flow Rate ◽  
Seismic Signals ◽  
High Heat Flow ◽  
Area North ◽  
Electric Signals

Abstract. The seismicity of the last 15 years in the Aegean Sea revealed that earthquakes (Mw > 5) with epicentres falling within the Sporades basin and the confined area north of Samos island were preceded by electric seismic signals (SES) with a remarkably long lead time. A possible explanation of this behaviour by means of specific tectonics and geodynamics which characterise these two regions, such as a significant small crustal thickness and a high heat flow rate, has been attempted. New data seem to strengthen the above hypothesis.

Effects of Crystallization Degree on Rate during Isothermal Crystallization from PET Melt

2012 ◽  
Vol 174-177 ◽  
pp. 1520-1523
Author(s):  
Hong Ya Zhang ◽  
Feng Wang ◽  
Hua Cheng
Keyword(s):  
Heat Flow ◽  
Flow Rate ◽  
Crystallization Process ◽  
Crystallization Rate ◽  
Polynomial Equation ◽  
Heat Flow Rate ◽  
Order Polynomial ◽  
Coefficient Vector ◽  
Crystallization Degree ◽  
Order Polynomial Equation

In this study, one new function is defined as change of relative crystallization degree in unit time and named relative crystallization rate (1/min.). The curve of heat flow rate to time is transmitted to that of to . The produced curve was fitted using one high-order polynomial equation with a variable of and the coefficient vector （Ai ,in this paper，the values of i were from 0 to 9）was produced. It was found that, even during the accelerated stage of crystallization from PET melt，both aspects to promote and delay the relative crystallization rate existed， furthermore， both aspects of promotion and delay declined with the crystallization process and appeared “internal exhaustion”.

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