Papers by Keyword: Ground Temperature

Abstract: The manuscript presents results of a 3 years experiment concerning the monitoring of temperature variation around a horizontal collector, coupled to a ground – water heat pump. Ground temperature was monitored in 7 (seven) measurement points: 1 (one) in the center of the collector area and 6 (six) at 15 cm, 30 cm and 60 cm of the collector boundary. The data processing methodology, described in the manuscript, allowed corrections, comparison with natural ground temperature variation and calculation of important characteristics of temperature variation in each measurement point. The main obtained results are: minimum, maximum and average temperatures, dates when minimum, maximum and average temperatures were reached, amplitude of temperatures variations and deviations comparing to natural ground temperature variation. The study of temperature field allowed the complete characterization of the ground temperature variation, including spatial and temporal variation. Some practical conclusions of the study are also presented in the manuscript. It was highlighted that due to a correct calculation of the collectors field size and to the presence of snow in each heating season of the 3 (three) years of the experiment, the ground temperature did not decreased below 2°C and the ground temperature recovered uniformly after each non heating season.

Abstract: This paper introduces a kind of low power ground temperature monitoring system based on CAN bus, the detection system adopts DS18B20 temperature sensor as the detecting element, under a machine with low power consumption of processor MSP430 MCU multi-channel temperature data collection, PC processors SMT32 is adopted to improve the data receiving and analysis. The ground temperature detection system has realized the low power consumption, strong anti-interference ability, low cost, has wide use value.

Abstract: Based on the data and laboratory analysis of Sun-Cun Coal Mine, the relationship between the geothermal gradient and the depth of mine in Suncun Coal Mine has been developed. According to this and the laboratory experiments, the relationship between spontaneous combustion period of coal seam and the depth of the mine has been obtained in this article. The results show that the law of coal seam spontaneous combustion period and the mine depth in accordance with the relationship of the gauss curve expression and when the coal mine depth is around 1000 m, the coal seam spontaneous combustion period shortened dramatically. This law should be pay more attention to.

Abstract: Our current storage work whether in grain storage concepts or grain storage technology with the green grain storage requirements have a large gap, due to national land resources increasingly tense at the same time, to save land and improve the quality of the food, the granary built underground is the trend, This paper by studying the different regions of our country's ground temperature, underground water, soil and other factors, and in accordance with the general principles of the partition,in accordance with the higher the score, the more favorable for the construction of underground building principle, using AHP to determine the weight of each indicator to study different regional underground grain storage buildings environmental suitability level, the establishment of underground grain storage environment regionalization research results to guide the construction of underground storehouse in our country has a certain application value.

Abstract: To analyze refreezing state and permafrost table of the frozen ground for the Qinghai-Tibet DC Transmission Line Engineering, temperature monitoring tests of fine-grained frozen soil were carried out and the thawing depth of backfilled soil was measured in Wudaoliang region of the Tibetan Plateau. The ground temperature fluctuates over time, and the fluctuation characteristics are determined by soil properties, climate, depth and other factors. The seasonally thawed layer is in the shallow of undisturbed frozen ground and backfilled soil. The maximum thawing depth of backfilled soil was about 2.3m more than permafrost table of the undisturbed frozen ground. Soil near the foundation slab was keeping frozen state. The results show that the construction of frozen ground in cold season is helpful to refreeze and keep frozen state of the ground, and can provide a basis for stability analysis of the engineering foundation.

Abstract: Taking the method of shotcrete and rock bolt support can effectively keep slope stability and prevent soil erosion, but this method also makes the local microclimate change. This paper is to discuss the microclimate effect of revegetation on concrete slope, which take the excavated slope in Guandi hydropower station as the research object. The results show that, vegetation can significantly reduce the ground temperature and increase humidity on concrete slope, and adjust humidity changes. Especially under the conditions of high temperature in sunny day, the microclimate regulation effect of vegetation on naked slope is more obvious.

Abstract: The invariable heat flux is always loaded in temperature simulation for grind-hardening. The heat flux is time-variant in actual process. The paper uses experiment result of grinding force to calculate out the time variation heat flux. The grinding temperature is simulated based on time variation heat flux by ANSYS software. The variation tendencies for the grinding force and the simulated surface top temperature will be discussed.

Abstract: It is essential to control the heat generated in the cutting zone in order to ensure the workpiece quality after grinding. This article deals with an investigation in using graphite and hexagonal boron nitride as solid lubricants to reduce friction and thereby improve the surface integrity of Ti-6Al-4V alloy. The polymer-based solid lubricant coating wheels have been prepared. Grinding experiments have been conducted to study the effect of the graphite and hexagonal boron nitride lubricants on the grinding temperature and the surface quality of the workpiece while grinding Ti-6Al-4V. Results indicate that there is a considerable improvement in the performance of grinding Ti-6Al-4V using graphite and hexagonal boron nitride as solid lubricants in dry grinding in terms of grinding temperature and surface quality of the work piece. The indigenous polymer-based solid lubricant coatings are effective in dry grinding.

Abstract: Ground white layer is caused primarily by grinding temperature induced phase transformation. So, it may form when grinding temperature exceeds the nominal phase transformation temperature. However, no attempt is made to investigate mechanical effect on formation of white layer. In this study, grinding temperature is measured by using thermocouple technique in grinding of AISI 52100 annealed steel. The specimens are investigated by using scanning electron microscope (SEM), energy disperse spectroscopy (EDS), micro hardness tester and X-ray diffraction (XRD). The microstructure and formation mechanism of white layer are analyzed. Ground whiter layer is confirmed to be composed of fine-grained cryptocrystalline martensite and retained austenite. High hardness of white layer is caused by transformation hardening through fine grain and high dislocation density due to severe deformation. White layer can form at temperatures below the nominal austenitization temperature of the material. Plastic deformation is also important in white layer formation during grinding process. High pressure on grinding surface exists under severe deformation. Phase temperature can be reduced due to high pressure; while crystal grain can be refined by plastic deformation. Oxidation and carburizing phenomenon exist during formation of white layer.

Abstract: The existing research shows that high-speed grinding is the main way to machining the common materials and difficult-to-machine materials efficiently and critically. However, the research on mechanism and high-speed characteristics of high-speed cylindrical grinding is few searched. Based on three-dimensional simulation software DEFORM-3D, the simulation model of high speed cylindrical grinding with single grit was established, and the relevant experiment of 3D simulation for high speed cylindrical grinding process was processed. In this paper, the impact of the grinding parameters, such as wheel speed and depth of cut on the grinding force and grinding temperature is explored through analyzing the variation of strain rate, grinding force and temperature, and found that the increasing strain rate can lead to the increase in grinding force and temperature. According to the simulation experiment results, the control model of grinding temperature for prediction of grinding temperature and optimization of grinding parameters, is analyzed and developed in the end. The engineering experiment, conducted on the high speed cylindrical grinder and measured grinding temperature with thermal infrared imager, has been carried out in this study. Engineering and simulation experiments results show good match, for grinding temperature would decline with the increasing wheel speed when the grinding depth keeps constant, and thus can reduce grinding burn, improve the surface quality of workpiece.