低温热水地板辐射采暖的发展优势及尚存问题

低温热水地板辐射采暖系统具有节约能源、减少环境污染、热舒适性好、卫生保健、初投资不高、维修费用低等优点,但在应用中尚存在一些问题,本文指出了其在设计和施工中存在的一些问题及相应的解决方法,同时通过对共约2000m^2实铺面积的统计,得出了不同管间距时单位面积大约所需的管长,根据经验提出了一种设计穹孽謦方孽虿母可哆使设计者节省设计时间,还可以避免管材浪费现象,节省工程成本。     

高温低氧燃烧技术在唐钢高线厂的应用

为了使应用高温低氧燃烧技术的加热炉达到高效节能、低污染物特别是低NO_x排放的目的,采用计算机数值模拟优化设计了加热炉的蓄热式燃烧系统,并运用冶金反应工程学方法开发了成套技术.该技术在唐钢高速线材厂的实际应用表明:在热装钢坯条件下单位能耗为0.879 GJ/t,炉子热效率在67%以上,各蓄热室的排烟温度在160℃以下,NO_x排放小于40×10^-6(体积分数).     

燃煤机组的供热改造项目实例分析

目的 为了提高燃煤机组的运行效率和经济效益,以珠海发电厂的供热改造项目为对象进行实例分析,探索煤电机组经营困境的破局之路。 方法 通过剖析珠海发电厂供热改造项目,从可行性、控制策略、改造效果等几个方面综合探讨。 结果 分析结果表明,供热改造后机组煤耗明显降低,同时供热量的增加提高热电比,可争取更多的计划电量,增加发电基数。 结论 供热改造对于条件合适的燃煤机组是一个值得参考的优化途径,具有非常重要的指导意义和经济价值。     

Oscillation propagation features of the atmosphere around the Qinghai-Xizang Plateau during the spring season of typical strong and weak monsoon years

The interaction between the low-frequency atmospheric oscillation(Madden-Julian Oscillation,MJO) and the diabatic heating over the Qinghai-Xizang Plateau(QXP) from March to June is analyzed.The results show that there are respectively two and one wave trains around the QXP during the onset of the South China Sea monsoon in strong and weak monsoon years.The locations and strength of the wave train propagation differ between the strong and weak monsoon years.Because diabatic heating of the QXP prevents the lo...     

高强度厚壁H型钢桩轧制工艺优化研究

针对莱钢高强度厚壁H型钢桩存在屈服强度波动较大以及性能不合的现象,通过对加热、轧制、冷却工艺进行优化改进,解决了高强度H型钢桩生产中的技术难题,使钢材的性能检验合格率由95%提升至97%,吨钢煤气消耗减少了0.1 GJ/t,保证了生产的顺行。     

钢丝非稳态加热的运行速度计算

在热处理钢丝时,大多在对流换热条件下对钢丝进行加热,铅浴热处理是其加热方法之一。本文根据传热学理论,依据能量守恒原理,应用集总热容法,对钢丝在第三类边界条件下的加热建立合适的数学模型,推导出第三类边界条件下的钢丝在对流换热情况时的加热时间计算式,给出了钢丝表面到温和钢丝中心到温时间表达式,由此导出钢丝非稳态加热的运行速度计算式,为钢丝热处理工艺的制定和钢丝加热炉(槽)的设计提供理论计算依据。     

Thermo-mechanical behaviour of a single slice test device for the FRIB high power target

One of the major challenges of the FRIB project (Facility for Rare Isotope Beams) at Michigan State University is the design and integration of the production target to produce rare isotope beams via fragmentation reaction. In the most extreme case, a 400 kW uranium beam of 200 MeV/u will be focused in a 1 mm diameter spot, leading to a power density of 60 MW/cm³ for a C target. Up to 200 kW may be dissipated in the target.A rotating solid carbon disk concept has been selected as the target design approach for all primary beams up to uranium to provide high-power operation. A high rotational speed is necessary to compensate for the high power density. A multi-slice approach allows the evacuation of the large amount of heat deposited by the increase of the radiating area. In the present design study, the multi-slice target device has a diameter of about 30 cm and rotates at about 5000 RPM (revolutions per minute). The first step of the R&D strategy consists in the development and test of a 20 kW single-slice target prototype. This single disk device is designed to accept the same fraction of power as each disk of the final multi-slice target. Critical information on thermal-mechanical properties can be obtained thus at a lower power level than the one of the full device. Different carbon materials were tested. An electron beam of ∼20 keV was used for the thermal tests. Simulations were performed using the ANSYS code for the thermo-mechanical behaviour of the target, the resulting deformation and the stress profiles of heated graphite disks. Results of the simulations were compared with experimental data.     

锌锅熔沟锌液流动方向成因分析及凝固后的处理方法探讨

本文根据电磁感应原理结合热动力学烟囱效应,分析了感应加热式锌锅锌液形成稳定流动原因,推导出锌锅两个感应加热器回路接线要使它们的磁场方向要相同的结论。锌锅感应加热器停电是严重的故障,会造成熔沟内锌液凝固。一旦熔沟内锌液发生凝固,必须采用长时间低功率来使熔沟内“锌锭”缓慢熔化,以释放锌锭受热产生的应力避免造成耐材损坏引起漏锌。初步探讨了一种采用集肤效应原理来快速解决熔沟内凝固“锌锭”的方法。     

Development of the heating and forming strategy in compound forging of hybrid steel‐aluminum parts

In times of increasing energy costs automotive light weight construction is gaining more importance. The production of hybrid compounds by forging is a promising method for manufacturing functional parts by applying resource‐saving process steps. The mechanical properties of these parts can be specifically adapted to the requirements. In compound forging of steel‐aluminum parts the two materials need to be heated to different forming temperatures. In this paper, the challenges and their methods for the development of a heating and forming strategy based on different material characteristics are presented.     

机械过冷跨临界CO_2热泵供暖系统性能分析

采用辅助的蒸气压缩循环进行过冷,可改善传统跨临界CO_2热泵系统用于冬季供暖性能。本文通过构建机械过冷跨临界CO_2热泵系统的热力模型,分析了机械过冷跨临界CO_2热泵系统供暖工况下的运行特性,结果表明:机械过冷CO_2热泵系统存在最大COP,对应最优排气压力和过冷度,标准工况下比常规CO_2系统能效提高15.9%。该系统可有效解决常规CO_2热泵回水温度过高导致COP迅速衰减的问题,当回水温度由40℃升至50℃时,常规系统COP下降16.9%,而机械过冷热泵系统COP仅下降8.4%。通过改进可有效降低CO_2压缩机的排气压力和温度,且供水温度越低排气压力降低效果越显著。机械过冷循环工质的选取会影响系统整体性能,选取的11种过冷循环工质中能效最高的为R717,最低的为R1234yf。在低环境温度工况下性能的提升更加明显,通过配置小型常规工质蒸气压缩循环即可实现CO_2热泵系统性能显著改进,经济性优势明显。