ANTENNA UNIT HEAT MODE

2021 ◽  
Vol 0 (10) ◽  
pp. 38-46
Author(s):  
Y.A. Divakova ◽  
Keyword(s):  
Surface Temperature ◽  
Thermal Regime ◽  
Convective Heat Exchange ◽  
Operating Conditions ◽  
Air Cooling ◽  
Average Surface ◽  
Heated Zone ◽  
Average Surface Temperature ◽  
Heat Mode ◽  
Forced Air

The article describes the procedure for calculating the thermal regime of a unit. The unit under study is part of a phased array. The calculation of the thermal regime allows you to verify the operability of the device under a steady thermal regime and to verify that the choice of the method of cooling the structure is correct. The work of the unit is analyzed under conditions of convective heat exchange without forced cooling at the maximum operating (permissible) ambient temperature. The calculation of the thermal regime of the unit is carried out in two stages. At the first stage, the temperature of the unit case is determined when the unit case overheats in the first approximation. The overheating value is determined from the graph. The calculation is carried out under conditions of natural air cooling. At the second stage, the average surface temperature of the heated zone is determined. The greatest heating in the unit is observed in the area occupied by the board with ERE. According to the results of the calculation, a problem was revealed, which consists in the fact that under the given operating conditions of the investigated device, the unit area is heated above the maximum operating temperature of some ERE. The value of the average surface temperature of the heated zone of the unit exceeds the value of the maximum allowable temperature of the least heat-resistant element of the heated zone. This means that it is necessary to use forced air cooling by air convection. The article proposes a solution to the problem of unit overheating, and describes the method of forced air cooling and its design.

scholarly journals LOW TEMPERATURES EFFECT ON THERMAL CONDITIONS OF DZ-98 AUTOGRADER HYDRAULIC UNITS

2020 ◽  
Vol 17 (3) ◽  
pp. 316-327
Author(s):  
T. N. Okhlopkov
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Ambient Temperature ◽  
Thermal Regime ◽  
Low Temperatures ◽  
Hydraulic System ◽  
Operating Conditions ◽  
Working Fluid ◽  
Climatic Data ◽  
Joint Stock Company

Introduction. The article discusses the climatic conditions of Yakutia, as well as the cooling process of the hydraulic system of DZ-98 motor grader in order to prevent violation of the thermal regime of hydraulic units under the influence of low temperatures, taking into account the wind blowing and operating conditions. The surface temperature of the hydraulic units was measured on January 16, 2018 in the city of Yakutsk on the basis of Yakutdorstroi joint-stock company at an ambient temperature of -42 ° С.Materials and methods. To ensure a reliable operation of the hydraulic system at low temperatures, hydraulic units must provide a supply of working fluid under pressure, regardless of changes in ambient temperature. The thermal regime of hydraulic units is characterized by three main parameters: pressure, temperature and volume. In the North, where the ambient winter temperature varies from -27 ° С to -49 ° С, the absolute temperature is the determining parameter. Studying the problem, theories of heat conduction and heat transfer in solids, hydrodynamics, and differential equations were used.Results. Natural and climatic data, as well as the recorded surface temperature of hydraulic units, allow to determine the number of days with a critically negative temperature, the heat transfer of hydraulic units and the regularity of its change depending on the operating mode.

An Integrated Model of Global Warming and Policy Making

2011 ◽  
Author(s):  
Zheming Zhang ◽  
Ramesh Agarwal
Keyword(s):  
Global Warming ◽  
Surface Temperature ◽  
Co2 Emissions ◽  
General Circulation ◽  
Co2 Concentration ◽  
Integrated Model ◽  
Co2 Mitigation ◽  
Average Surface ◽  
Global Average ◽  
Average Surface Temperature

This paper describes a simple integrated model of global warming due to anthropogenic CO2 emissions, which can help the policy makers in considering various CO2 mitigation strategies. First, the constant airborne fraction model is generalized to establish relationship between CO2 emissions and CO2 concentration in the atmosphere which is then used to determine the global average surface temperature using the Oglesby and Saltzman’s general circulation model. Using these simple relationships, the forecast for CO2 emissions, CO2 concentration and average global surface temperature is made for years 2030 and 2050 under Business as Usual (BAU) scenario. In order to achieve an acceptable target increase in global average surface temperature, several simple CO2 mitigation approaches, proposed by Socolow and Lam, are included in the integrated model.

On the strongly negative cloud feedback over the satellite period implied by observational SST reconstructions

2021 ◽  
Author(s):  
Stephan Fueglistaler ◽  
Levi Silvers
Keyword(s):  
Surface Temperature ◽  
General Circulation ◽  
Deep Convection ◽  
Historical Period ◽  
Surface Temperature Change ◽  
Average Surface ◽  
Global Average ◽  
Coupled Gcm ◽  
Average Surface Temperature ◽  
Second Mode

<p>Clouds strongly modulate Earth's radiative budget, and uncertainties in numerical model simulations of the global cloud field contribute substantially to uncertainties in future warming. In coupled atmosphere-ocean General Circulation Model (GCM) simulations, the global cloud field and its radiative effect are well correlated with global average surface temperature. However, GCM simulations with prescribed Sea Surface Temperatures (SSTs) from observational SST reconstructions over the historical period show time-varying relationships between the cloud field and average surface temperature (known as the "pattern effect"). We show that CERES/EBAF observational data confirms the presence of a second mode (in addition to mean SST) in particular in low cloud amount (and correspondingly SWCRE) that is consistent with variations in tropical atmospheric stability in ERA-Interim reanalysis data. This second mode in observations is tied to ENSO, and evolves in quadrature to ENSO indexes. It arises from differences in surface temperature change between regions of tropical deep convection and the tropical (or global) average. In contrast to the multidecadal trends over the full historical period, trends in this second mode since the year 2000 are small. The PCMDI/AMIPII SSTs recommended for CMIP6 stand out as having the largest trend over the full historical period. Different SST reconstructions agree on a trend over the satellite period - specifically the 1980s-90s - that is much larger than what coupled GCM simulations show: In forced coupled GCM simulations the regions of deep convection warm order 10% more than the tropical average, whereas over the satellite period the amplification is order +50%  in the AMIP simulations and in estimates using rainfall observations to identify regions of deep convection.</p>

An Analysis of Various Cooling Liquids in a Two-Cylinder Single-Stage Piston Hybrid Power Machine with Fluid Flow Due to Vacuum at Suction Based on Experimental Results

2020 ◽  
pp. 40-49
Author(s):  
V.E. Shcherba ◽  
G.S. Averyanov ◽  
S.A. Korneev ◽  
S.V. Korneev ◽  
A.Y. Ovsyannikov ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Surface Temperature ◽  
Distilled Water ◽  
Average Surface ◽  
Working Chamber ◽  
Hybrid Power ◽  
Average Surface Temperature ◽  
Transmission Oil ◽  
Power Machine ◽  
Hybrid Power Machine

This paper examines the use of various types of cooling liquids in a two-cylinder single-stage piston hybrid power machine with fluid flow due to vacuum at suction. Liquids with various basic thermal properties were used as working fluids: distilled water, antifreeze, and transmission oil. Specific heat capacities and dynamic viscosities of these liquids differed from 2 to 10 times. The experimental studies showed that the greatest cooling effect on the cylinder-piston group was observed when using distilled water, and the least — when using transmission oil. The average surface temperature of the working chamber when cooled with water was minimal in the range of 330–340 K. The average surface temperature of the working chamber when cooled with transmission oil was maximum and ranged from 345 to 355 K, i. e. it was about 15 K higher than when cooled with water. The average surface temperature of the working chamber when cooled with antifreeze occupied an intermediate position between the average temperatures of the working chamber when cooled with water and that with transmission oil and was in the range of 335–345 K, i. e. about 5 K higher than when cooled with water.

Determination of Thermal Barrier Coatings Average Surface Temperature After Engine Operation for Lifetime Validation

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Barrier Coatings ◽  
Average Surface ◽  
Barrier Coating

Assessment of ex-service parts is important for the power generation industry. It gives us the opportunity to correlate part conditions to specific operating conditions like fuel used, local atmospheric conditions, operating regime, and temperature load. For assessment of thermal barrier coatings, one of the most valuable pieces of information is the local thermal condition. A method has been developed in Alstom, allowing determination of a thermal barrier coating average surface temperature after engine operation. It is based on the analysis of the phase composition of the thermal barrier coating by the acquisition of an X-ray diffraction spectrum of the coating surface, and its analysis using Rietveld refinement. The method has been validated by comparing its outcome to thermal models and base metal temperature mapping data. It is used for assessment of combustor and turbine coatings with various purposes: Determination of remnant coating life, building of lifing models, or determination of the coating degradation mechanisms under some specific operating conditions. Examples will be presented showing applications of this method.

scholarly journals Assessing the efficiency of green roof technology: A case study of Masjid Kota Iskandar, Nusajaya, Johor

2018 ◽  
Vol 250 ◽  
pp. 06011
Author(s):  
Muhamad Hanafi Rahmat ◽  
Muhd Hariz Mohkatar ◽  
Izudinshah Abd Wahab ◽  
Nur Nasuha Abd Salam ◽  
Hazri Abdul Aziz ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Surface Temperature ◽  
Engineering Design ◽  
Green Roof ◽  
Infrared Thermometer ◽  
Average Surface ◽  
Minimum Surface ◽  
Average Surface Temperature ◽  
Hot Climate

Green roof is a system that had been identified as a medium that is able to reduce the thermal temperature of a building. It is an efficient way of reducing heat especially for hot climate countries like Malaysia. This study was conducted to assess the ability and the effectiveness of green roof in controlling the temperature of a building and also to make a comparison of its performance with the conventional roof. The study was conducted at the Masjid Kota Iskandar, Nusajaya, Johor. For this case study, Infrared Thermometer and 4 in 1 Meter Kit were used to record the temperature (maximum and minimum) during the day on the surface of the green roof and conventional roof as well as its relative humidity. The experiments were conducted during sunny days from 8.00 am to 6.00 pm at an interval of two hours on two different dates which were 18th March 2017 and 4th April 2017. Few locations for the data to be collected were plotted on the surface of both roofs and the readings of maximum and minimum surface roof temperatures were recorded for comparison. Based on the research that had been carried out, it can be concluded that the usage of green roof was able to reduce the average surface temperature in the range of 3.6°C –11.1°C as compared to the conventional roof. This result had proven that there was a decrease in temperature for the green roof as compared to the conventional roof. It had shown that the usage of the green roof in a building was an efficient way of reducing building temperature and also an effective way to achieve sustainability in architecture and engineering design.

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