Determination of Heat Loss from the Feet and Insulation of the Footwear

This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of thermal foot method, the latter should be preferred for testing.     

A Comparison of Two Methods of Determining Thermal Properties of Footwear

The present European Standard for footwear testing (Standard No. EN 344:1992; European Committee for Standardization [CEN], 1992) classifies footwear thermally by a temperature drop inside the footwear during 30 min at defined conditions. Today, other methods for footwear thermal testing are also available. The aim of this study was to compare EN 344:1992 with a thermal foot method. Six boots were tested according to both methods. Additional tests with modified standard tests were also carried out. The methods ranked the footwear in a similar way. However, the test according to standard EN 344:1992 is a pass-or-fail test, whereas data that is gained from the thermal foot method gives more information and allows further use in research and product development. A change of the present standard method is suggested.     

Effect of Sweating on Insulation of Footwear

The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19–25% (30–37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.     

Analytical Study of the Heat Loss Attenuation by Clothing on Thermal Manikins Under Radiative Heat Loads

For wearers of protective clothing in radiation environments there are no quantitative guidelines available for the effect of a radiative heat load on heat exchange. Under the European Union funded project ThermProtect an analytical effort was defined to address the issue of radiative heat load while wearing protective clothing. As within the ThermProtect project much information has become available from thermal manikin experiments in thermal radiation environments, these sets of experimental data are used to verify the analytical approach. The analytical approach provided a good prediction of the heat loss in the manikin experiments, 95% of the variance was explained by the model. The model has not yet been validated at high radiative heat loads and neglects some physical properties of the radiation emissivity. Still, the analytical approach provides a pragmatic approach and may be useful for practical implementation in protective clothing standards for moderate thermal radiation environments.     

Testing Sleeping Bags According to EN 13537:2002: Details That Make the Difference

The European Standard on sleeping bag requirements (EN 13537:2002) describes a procedure to determine environmental temperature limits for safe usage of sleeping bags regarding their thermal insulation. However, there are several possible sources of error related to this procedure. The main aim of this work was to determine the influence of the various measuring parameters on the acuity of the respective parameters in order to judge the requirements. The results indicated that air velocity, mattress insulation and time between unpacking the bag and measurement had a significant impact on the result, with a difference of up to 5–15% in thermal insulation between minimum and maximum allowable parameter levels. On the other hand, manikin weight, thickness of the artificial ground and presence of a face mask were found to have a negligible influence. The article also discusses more general aspects of the standard including the calculation methods used.     

浙江省火电行业主要污染物减排环境效益研究

利用美国环保局开发的新一代空气质量模式系统Models-3,对2010 年浙江省大气污染物进行数值模拟研究,并对SO₂、NO₂ 和PM₁₀ 等大气污染物浓度的模拟结果与监测结果进行了对比分析。结果表明,Models-3 系统能较好地反映浙江省的大气污染情况,模拟值与观测值的变化趋势具有较好的一致性,说明该模式能较好地进行大气污染物的分布特征和变化规律的研究。为定量分析电力行业多污染物协同控制与区域复合型大气污染之间的定量关系,评估不同控制情景下的环境质量效益,应用CMAQ 空气质量模型分别对2010 年基准排放情景和火电行业主要污染物(SO₂、NO_x 和烟尘)的三套减排控制情景,评价环境空气污染物SO₂、NO_x、PM_2.5 和PM₁₀ 状况进行模拟,评价污染物减排的环境效益。三套方案下PM_2.5 浓度下降比例分别为0.53%、0.55% 和0.57%,其中重点区域浓度下降比例分别为4.36%、4.38%和5.9%;PM₁₀ 浓度下降比例分别为0.40%、0.42% 和0.65%,重点区域下降比例分别为3.42%、5.82% 和8.16%;NO_x 浓度下降比例分别为12.4% 和13.3%,重点区域下降比例分别为13.8% 和16.9%;SO₂ 下降比例平均为11.24%,其中重点区域下降比例为14.4%。SO₂、NO_x 和烟(粉)尘协同减排对于浙江地区特别是重点区域的环境空气质量改善有着显著意义。     

Effect of bioethanol and thermal barrier coating on the performance of dual fuel engine operating on Honge oil methyl ester (HOME) and producer gas induction

Alternative fuels have numerous advantages compared to fossil fuels as they are renewable, biodegradable; provide energy security and foreign exchange saving besides addressing environmental concerns and socio-economic issues as well. Renewable fuels can be used predominantly as fuel for both transportation and power generation applications. Improved engine performance with reduced engine exhaust emissions is a major research objective in engine development. Today, the use of biomass derived producer gas is more relevant for addressing rural power generation and is a promising technique for controlling both nitric oxide (NO_x) and soot emission levels. In view of this, exhaustive experiments on the use of Honge oil methyl ester (HOME)–Producer gas in a dual fuel engine have been carried out with an intension of improving its fuel efficiency. This paper mainly presents results on a single cylinder four stroke direct injection diesel engine operated in dual fuel mode using HOME–Producer gas combination with and without bio-ethanol addition and thermal barrier coating (TBC). Further, the results were compared with diesel–producer gas mode of operation. Experimental investigation on dual fuel operation using HOME+5% bioethanol (BE5)–Producer gas operation with TBC showed 12.35% increased brake thermal efficiency with decreased hydrocarbon and carbon monoxide emissions and increased NO_x emission levels compared to HOME–Producer gas mode of operation.     

Experimental analysis of thermal performance of evacuated tube and flat-plate solar air collectors at different air flow rates

The thermal performances of an evacuated tube collector (ETC) and flat-plate solar air collector (FPC) are experimentally investigated at different air flow rates. To investigate the performance of the ETC and FPC, experimental set-ups were fabricated. Air was used as a working fluid and tested at the same climatic conditions. The ETC had 15 evacuated tubes with a surface area of 1.66 m². The experimental set-up consisted of a header with a hollow pipe (square pipe) in the centre through which the air flowed. The flat-plate collector had a surface area of 1.35 m². The FPC had a black painted absorber sheet which divides the collector into two sections. The air flowed through the upper and the lower sections parallel to the collector to minimize the overall heat loss. The temperature of the outlet air depends on several factors along with the airflow rate and the intensity of the solar radiation. It was found that during the day at high flow rates, the efficiency of the ETC varies from 0.12 to 0.5, and for the flat plate it was from 0.29 to 0.68. The maximum temperature of the air was 56.7°C for the ETC and 25.7°C for the FPC.     

比较FDS和FLUENT在池火灾模拟中的应用

热辐射是池火灾燃烧的主要危害之一,可能导致人员伤亡或设备设施损坏。油罐火灾是典型的池火灾。本文通过对无风情况下油罐火灾火焰形状进行理论模型分析,建立了各自的物理模型和几何模型。应用计算流体动力学软件Fluent和火灾动力学模拟软件FDS,对无风情况下池火灾对周围大气环境的热辐射强度进行模拟,得到了火焰周围入射热流密度分布图,运用软件Statistica拟合得出热辐射强度与距离火焰中心的水平距离的对应关系,分别计算出轻伤半径区域下的最小安全距离。数值模型模拟结果与池火灾经验模型进行比较,发现FDS辐射强度结果与经验模型结果吻合较好。分析了利用这两种模型模拟油罐火灾各自的优点和缺点,最后提出了运用FDS软件模型模拟油罐火灾时的优势。     

氨法烟气脱硫工艺在燃煤锅炉的应用

介绍了氨法脱硫技术在国内外的应用情况以及氨法烟气脱硫工艺的工作原理和工程应用难点;分析了热电厂煤粉锅炉烟气脱硫的工艺路线特点及新型氨法脱硫工艺应用后取得了的显著效果;提出了氨法脱硫工艺存在的问题和发展前景。