为防止卡车在长时间刹车后,刹车鼓温度过热或高负载情况下差速器油温过高而发生事故,文章设计一种基于STM32F429和STM32F103单片机协同工作的卡车刹车鼓温度、差速器油温监控与预测系统。该系统以STM32F429单片机为主处理器,利用控制器...为防止卡车在长时间刹车后,刹车鼓温度过热或高负载情况下差速器油温过高而发生事故,文章设计一种基于STM32F429和STM32F103单片机协同工作的卡车刹车鼓温度、差速器油温监控与预测系统。该系统以STM32F429单片机为主处理器,利用控制器局域网(controller area network,CAN)总线和以STM32F103为核心的从处理器进行及时数据传输和存储,并融入STemWin系统设计人机交互界面,基于自回归求积移动平均理论建立温度预测模型。仿真结果表明:该系统稳定可靠、预测精准,能有效减少因刹车鼓温度或差速器油温过高而引起的事故。展开更多
温度预测模型是实现基于分布式温度测试(distributed temperature sensors,DTS)解释产出剖面的基础,但定量预测低渗气藏压裂水平井温度剖面仍是一个难题。为此,建立一套考虑多种微热效应的低渗气藏压裂水平井耦合温度预测模型,模拟一口...温度预测模型是实现基于分布式温度测试(distributed temperature sensors,DTS)解释产出剖面的基础,但定量预测低渗气藏压裂水平井温度剖面仍是一个难题。为此,建立一套考虑多种微热效应的低渗气藏压裂水平井耦合温度预测模型,模拟一口低渗气藏压裂水平井的温度剖面,分析温度剖面特征,并采用正交试验分析法评价压裂水平井温度剖面对不同因素的敏感性。研究结果表明:①压裂水平井温度剖面呈现出不规则的“锯齿状”,任一“锯齿”都对应着一条有效人工裂缝;②各级裂缝处的井筒温降基本上与裂缝半长正相关;③从趾端到跟端,各级裂缝位置处的井筒温降与裂缝半长的比值(ΔT/x f)依次递减;④压裂水平井温度剖面对各因素的敏感性依次为:裂缝半长>产量>地层渗透率>井筒半径>地层孔隙度>裂缝导流能力>水平倾角。研究成果为实现基于DTS解释压裂水平井产出剖面提供了模型基础和理论支撑,对于压裂水平井改造效果评价和出水位置定量诊断具有重要意义。展开更多
针对目前氢燃料重卡在行驶过程中,动力电池工况复杂、外表面温度变化难以预测、滞后时间长等问题,以氢燃料重卡锂离子动力电池外表面温度为研究对象,提出一种类交叉熵损失函数和自适应矩估计(adaptive moment estimation,Adam)优化的改...针对目前氢燃料重卡在行驶过程中,动力电池工况复杂、外表面温度变化难以预测、滞后时间长等问题,以氢燃料重卡锂离子动力电池外表面温度为研究对象,提出一种类交叉熵损失函数和自适应矩估计(adaptive moment estimation,Adam)优化的改进型门控循环单元神经网络(gate recurrent unit,GRU),建立锂离子动力电池表面温度预测模型。该模型利用GRU神经网络的特殊门机制和全局处理能力,得到锂离子电池表面温度和电池充放电电流、电压、充放电时间、历史温度、当前温度以及环境温度之间的非线性关系。采用4个精度评价函数对预测模型进行评价:经过5种环境温度下的模拟工况实验,验证该模型的准确性。结果表明,基于GRU的电池温度预测模型的误差相对于反向传播(back propagation,BP)神经网络模型和循环神经网络模型(recurrent neural network,RNN)来说较小,说明GRU的锂离子电池温度预测模型具有更高的精度。该文为磷酸铁锂电池表面温度的精准预测提出了一种新的方法。展开更多
The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or...The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or nighttime radiation cooling and should not be simplified as one dimensional. A temperature predicting model that can accurately predict temperatures over the cross section of the concrete box girder was developed. On the basis of the analytical model, a two-dimensional temperature gradient model was proposed and a parametric study that considered meteorological factors was performed. The results of sensitivity analysis show that the cold wave with shorter duration and more severe temperature drop may cause more unfavorable influences on the concrete box girder bridge. Finally, the unrestrained linear curvatures, self-equilibrating stresses and bending stresses when considering the frame action of the cross section, were derived from the proposed temperature gradient model and current code provisions, respectively. Then, a comparison was made between the value calculated against proposed model and several current specifications. The results show that the cold wave may cause more unfavorable effect on the concrete box girder bridge, especially on the large concrete box girder bridge. Therefore, it is necessary to consider the thermal effect caused by cold wave during the design stage.展开更多
文摘为防止卡车在长时间刹车后,刹车鼓温度过热或高负载情况下差速器油温过高而发生事故,文章设计一种基于STM32F429和STM32F103单片机协同工作的卡车刹车鼓温度、差速器油温监控与预测系统。该系统以STM32F429单片机为主处理器,利用控制器局域网(controller area network,CAN)总线和以STM32F103为核心的从处理器进行及时数据传输和存储,并融入STemWin系统设计人机交互界面,基于自回归求积移动平均理论建立温度预测模型。仿真结果表明:该系统稳定可靠、预测精准,能有效减少因刹车鼓温度或差速器油温过高而引起的事故。
文摘温度预测模型是实现基于分布式温度测试(distributed temperature sensors,DTS)解释产出剖面的基础,但定量预测低渗气藏压裂水平井温度剖面仍是一个难题。为此,建立一套考虑多种微热效应的低渗气藏压裂水平井耦合温度预测模型,模拟一口低渗气藏压裂水平井的温度剖面,分析温度剖面特征,并采用正交试验分析法评价压裂水平井温度剖面对不同因素的敏感性。研究结果表明:①压裂水平井温度剖面呈现出不规则的“锯齿状”,任一“锯齿”都对应着一条有效人工裂缝;②各级裂缝处的井筒温降基本上与裂缝半长正相关;③从趾端到跟端,各级裂缝位置处的井筒温降与裂缝半长的比值(ΔT/x f)依次递减;④压裂水平井温度剖面对各因素的敏感性依次为:裂缝半长>产量>地层渗透率>井筒半径>地层孔隙度>裂缝导流能力>水平倾角。研究成果为实现基于DTS解释压裂水平井产出剖面提供了模型基础和理论支撑,对于压裂水平井改造效果评价和出水位置定量诊断具有重要意义。
基金Project(08Y60) supported by the Traffic Science’s Research Planning of Jiangsu Province,China
文摘The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or nighttime radiation cooling and should not be simplified as one dimensional. A temperature predicting model that can accurately predict temperatures over the cross section of the concrete box girder was developed. On the basis of the analytical model, a two-dimensional temperature gradient model was proposed and a parametric study that considered meteorological factors was performed. The results of sensitivity analysis show that the cold wave with shorter duration and more severe temperature drop may cause more unfavorable influences on the concrete box girder bridge. Finally, the unrestrained linear curvatures, self-equilibrating stresses and bending stresses when considering the frame action of the cross section, were derived from the proposed temperature gradient model and current code provisions, respectively. Then, a comparison was made between the value calculated against proposed model and several current specifications. The results show that the cold wave may cause more unfavorable effect on the concrete box girder bridge, especially on the large concrete box girder bridge. Therefore, it is necessary to consider the thermal effect caused by cold wave during the design stage.
