共查询到20条相似文献,搜索用时 62 毫秒
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建立了内置式温差发电器的物理和数学模型,并对该模型进行了详细的阐述,网格划分和数值仿真完成后,得到了稳态下内板的温度分布场。通过对内板温度场的研究和分析可以得到结论:降低冷却液温度和提高冷却液流速有助于提高内置式温差发电器的发电性能,梅花形结构内板的内置式温差发电器的发电性能比一字形结构内板的内置式温差发电器的发电性能更好。该结论对提高内置式温差发电器的发电性能和优化内置式温差发电器的结构有着重要作用。 相似文献
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不锈钢筒形件的温差拉深数值模拟研究 总被引:1,自引:0,他引:1
温差拉深可以提升金属板料的成形性,减少引伸成形的拉伸次数。温差拉深时,温度是影响成形的重要因素。用PAM-STAMP对Cr18Ni9不锈钢筒形件的温差拉深工艺进行了模拟,分析了温度对温差拉深的影响,为筒形件温差拉深工艺的制定提供了依据。 相似文献
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在恒定泵功0.05 W条件下,对水冷铜基和铝基微通道热沉对流换热进行详细数值模拟和结构优化。通过将数值预测结果与前人已发表的试验结果进行对比,验证所使用的数值模型的正确性。同时讨论在恒定泵功下微通道几何结构对微通道热沉中温度分布的影响。模拟结果显示水冷铜基微通道热沉最优的几何结构参数为通道深为580μm,通道宽为90μm,通道密度为100个/cm;铝基微通道热沉最优的几何结构参数为通道深为620μm,通道宽为80μm,通道密度为100个/cm。 相似文献
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基于Fluent的超音速喷嘴的数值模拟及结构优化 总被引:1,自引:0,他引:1
对超音速laval喷嘴进行了热力学计算及几何参数计算,确定了喷嘴的几何尺寸。利用Fluent软件对喷嘴内流场进行数值模拟,得到了喷嘴内流场的分布规律。改变喷嘴的结构,分析了收缩段和扩张段的不同结构对喷嘴出口速度的影响。结果表明,喷嘴内气流的温度和压力逐渐减小,速度逐渐增大,说明了气流经历的是减压增速降温的膨胀过程,并验证了喷嘴设计的合理性。收缩段的结构对喷嘴出口速度基本没有影响,而出口直径对出口速度有较大影响,并以此为依据得出了结构优化后的喷嘴尺寸,对于今后超音速喷嘴的理论研究及优化设计具有一定的参考作用。 相似文献
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采用有限元法对小霸王轻型卡车转向节终锻成形过程进行研究,利用Pro/E对转向节及其模具进行三维建模,运用Deform进行闭模终锻分析,通过改变模具型腔杆部与墩头过渡圆弧半径及耳部拔模斜度参数的大小,对比不同参数对终锻过程中锻压力变化规律和应变、温度分布规律的影响,优化出了合理的模具参数:杆部与墩头过渡圆弧半径为5 mm左右,耳部拔模斜度为5o左右. 相似文献
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《Measurement》2016
We present a combined experimental and computational investigation of the transient behavior of a thermoelectric generator (TEG) subjected to temperature gradients of less than 0.5 K across its thickness. Such conditions can exist when TEGs are used as heat sensors or IR detectors. Spatially non-uniform heating was initiated by allowing light to strike the central portion of one side of the TEG or by placing a small heated probe in contact with that surface. The time-dependent, open circuit voltage output of the TEG was predicted using temperature results from a three dimensional transient heat conduction finite element model. It is shown that the transient voltage output is influenced by the configuration of the mounting hardware, by the thermal properties of the TEG’s materials of construction, and by convection. Three-dimensional heat conduction in the TEG determines the nature of the transient voltage output, which, in some cases, exhibits an overshoot. 相似文献
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采用刚塑性有限元对方截面管零件的轴压液力成形过程进行数值模拟,预测其成形结果及可能出现的质量问题,为模具设计及加载路径的优化提供理论依据。 相似文献
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J.P. Carmo Joaquim Antunes M.F. Silva J.F. Ribeiro L.M. Goncalves J.H. Correia 《Measurement》2011,44(10):2194-2199
Solid-state thermoelectric generators (TEGs) based on the Seebeck effect to convert temperature gradients, ΔT [K], into electrical energy are being used in an increased number of stand-alone microsystems applications. These generators are composed by at least one pair of p- and n-type thermoelectric elements with high figures-of-merit, ZT, to perform such a conversion. The exact behavior knowledge of generators is mandatory in order to decide the most suitable for the target application. The focus of this paper is to present a methodology to characterize thermoelectric generators, by measuring their behavior for different types of loads. The measurements were done with the help of commercial thermoelectric generators (thermoelectric modules TEC1-12707) and a measurement setup composed by a controlled hot-plate, a controlled cooling fan (above an heat dissipator), a set of two thermistors for measuring the temperature, a personal computer with the data acquisition board model NI USB-6009 and the LabView software from National Instruments for acquiring the measures and for controlling both the hot-plate and the cooling fan. The thermoelectric modules TEC1-12707 was selected due to its compact size (e.g., 40 mm × 40 mm) and because it can withstand temperatures up to 450 K without degrading the quality of measurements. A SPICE model for thermoelectric modules TEC1-12707 was also obtained: an open-circuit voltage of Vopen = 53.17 × ΔT [mV] and an internal resistance of R0 = 3.88 Ω with a tolerance of ΔRint = 0.13 Ω such that Rint = R0 ± ΔRint = 3.88 ± 0.13 Ω. The measurements done under the maximum output power delivery condition (for the maximum temperature gradient of ΔT = 51 °C) resulted in the maximum output power of Pout = 500 mW, as well as in the output current and voltage of Iout = 357 mA and Vout = 1.40 V, respectively. The load resistance of 3.92 Ω (Vout/Iout) is also in accordance with the measurements because it is located in the range [μ − σ, μ + σ] Ω, where μ = R0 = 3.88 Ω and σ = ΔRint = 0.13 Ω. An Agilent multimeter model 34410A with 6½ digits was used for measuring the voltages at the TEG’s output and the respective currents. 相似文献
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氩氧炉(AOD)是生产不锈钢最常用的精炼炉,由于其体积和重量大,加之内装钢水,使得其重量超过一百吨。为了保证氩氧炉安全运行,炉体托圈对氩氧炉支持强度至关重要。应用有限元方法对托圈进行了强度分析,得到了托圈在不同转角位置下的最大应力以及分布规律,获得了应力随转角的变动曲线,为氩氧炉安全运行提供了可靠数据,并为大型设备安全强度设计提供了较好数值分析方法和计算方法。 相似文献
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Biplab Paul 《Measurement》2012,45(1):133-139
A simple apparatus for the simultaneous measurement of Seebeck coefficient (α) and electrical resistivity (ρ) in the temperature range 100-600 K, Hall coefficient (RH) and transverse Nernst-Ettingshausen coefficient (N) in the temperature range 300-600 K of the bar shaped samples has been fabricated. The instrument has been designed so simply that the sample can be easily mounted for the fast measurements of different thermoelectric parameters. The sample holder assembly of the apparatus has been designed so cleverly that any part of that section can be replaced in case of any damage; and so it can be regarded as a modular based system. The apparatus is relatively cheaper in cost and also portable. 相似文献
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针对空气预热器中传热性能低下的问题,将纵向涡器运用于空气预热器热管内,以烟气为介质,运用计算软件FLUENT进行数值模拟,研究在不同Re数下,涡发生器对管内烟气的传热及流动阻力的影响,比较了不同攻角及翼高与管内半径之比的直角三角翼涡发生器强化换热效果,并与光管的换热系数和阻力系数进行了对比。分析表明,纵向涡发生器能明显提高换热性能,在所研究的纵向涡发生器中,攻角为45°时,涡发生器强化传热效果较好。随着Re数的改变,具有最佳传热效果的涡发生器结构也会有所不同。 相似文献
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多腔壁板铝型材挤压过程数值模拟及模具优化 总被引:6,自引:2,他引:6
挤压模具在铝型材挤压生产中起着至关重要的作用,挤压模具设计的优劣直接影响挤压产品的质量。然而实际生产中,挤压模具的设计更多依赖传统设计经验,需要多次试模和修模,无法满足产品开发需求。以典型的多腔壁板铝型材为例,应用UG建立分流组合模几何模型,采用基于任意拉格朗日—欧拉(Arbitrary Largrang-Euler,ALE)算法的HyperXtrude软件对多腔壁板铝型材的挤压成形过程进行数值模拟,获得挤压过程中速度场、温度场、应力场及金属流动情况。针对初始模具设计的不足,提出多腔壁板铝型材挤压模具优化三步曲(开设引流槽、增设阻流块、优化工作带),有效地解决了初始模具设计中速度分布不均的问题。利用数值模拟方法可以优化模具结构,提出的多腔壁板铝型材挤压模具优化三步曲对同类铝型材挤压模具结构设计具有一定的指导意义。 相似文献
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为了考察设计方案中增压锅炉烟气发生器的阻力大小及流场条件能否满足系统设计要求,采用FLUENT程序,对增压锅炉烟气发生器设计结构方案的燃烧流场及阻力进行了数值分析,同时考察了发生器的污染物排放性能。数值模拟时采用了RNGk-ε湍流模型、P-1辐射模型、液体燃料喷雾燃烧过程的颗粒轨道模型和PDF燃烧模型,对设计方案的压力场、温度场及NOx排放进行分析,得到了设计方案的阻力特性、温度分布和排污特性。结论表明:该方案的阻力大小及出口温度能够满足设计要求。该工作为优化烟气发生器结构和污染控制具有重要的指导意义。 相似文献
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基于计算流体动力学的两栖车辆水动力特性数值计算 总被引:8,自引:1,他引:7
应用计算流体动力学(Computational fluid dynamics,CFD)理论,建立某型两栖车模型带自由表面粘性绕流场的数学模型,阐述求解的数值计算方法.采用RNG κ-ε湍流模型、流体体积法(volume of fluid,VOF)和压力隐式算子分割(Pressure implicit with splitting ofoperators,PISO)算法,运用FLUENT软件对车体绕流场进行三维瞬态数值计算,得到绕流场的速度与压力分布、阻力和兴波特性,并结合相关试验数据验证了数值方法的正确性,解决了以往由于忽略兴波特性导致数值计算结果随航速提高误差不断增大的问题.在此基础上,对该两栖车外形提出了优化方案,计算分析车体首、尾端切角及车轮不同收、放状态对绕流场的影响.计算结果表明,两栖车改进后的水动力性能有了较大改善,航速10 km/h时,减阻效果可达原车总阻力的51.2%,为减阻提速的研究提供了一定的参考. 相似文献