折板式间接蒸发冷却器应用主要影响因素分析

制作了可用于纺织细纱车间的折板式间接蒸发冷却器试验台,通过实验研究来分析折板式间接蒸发冷却器在纺织细纱车间应用时的主要影响因素。首先借助于正交实验表,通过9组实验来分析折板式间接蒸发冷却器的三种主要影响因素对折板式间接蒸发冷却器的换热效果的显著程度。然后引入单因素实验的研究方法,在保证其它影响因素为最优的情况下,研究某一主要影响因素变化导致换热效率变化的规律,为实际工程的设计和节能运行调节提供理论依据。     

周期性条件下外保温空心砖墙体传热性能的数值计算与分析

采用数值计算方法,计算分析了带外保温层结构的空心砖墙体在周期性非稳态边界条件下,墙体内部的温度分布及传热量,分析研究了不同孔型空心砖传热性能的差异,得出保温层厚度对空心砖墙体的非稳态传热性能的影响.     

A novel ellipsoidal acoustic infinite element

A novel ellipsoidal acoustic infinite element is proposed. It is based a new pressure representation, which can describe and solve the eUipsoidal acoustic field more exactly. The shape functions of this novel acoustic infinite element are similar .to the Burnett‘s method, while the weight functions are defined as the product of the complex conjugates of the shaped functions and an additional weighting factor. The code of this method is cheap to generate as for 1-D element because only 1-D integral needs to be numerical. Coupling with the standard finite element, this method provides a capability for very efficiently modeling acoustic fields surrounding structures of virtually any practical shape. This novel method was deduced in brief and the conclusion was kept in detail. To test the feasibility of this novel method efficiently, in the examples the infinite elements were considered, excluding the finite elements relative. This novel eUipsoidal acoustic infinite element can deduce the analytic solution of an oscillating sphere. The example of a prolate spheroid shows that the novel infinite element is superior to the boundary element and other acoustic infinite elements. Analytical and numerical results of these examples show that this novel method is feasible.     

一种新的声椭球无限单元

提出了一种新的声椭球无限单元．这种声无限单元基于一种新的声压表达式,这种声压表达式能够更准确地代表着椭球声场的声传播模式．这种新方法的形函数类似于Burnett方法,而权函数定义为形函数和一个附加因子的乘积．因为仅需要一维的数值积分,这种新方法的代码生成十分容易,就像处理一维单元一样．耦合标准的有限元程序,这种声无限单元理论上能够高效地求解任何形状的声源的声辐射和声散射现象．简要地推导了这种新方法,并给出了这种方法详尽的推导结果．为更有效地检验该无限元方法的可行性,文中例子仅考虑无限元求解的精度,而不包括相应的有限元．使用这种新方法,精确地推导出了摆动球的理论计算公式．而长旋转椭球的例子则表明了这种方法优于边界元方法和其他声椭球无限元方法．这些例子表明了这种新方法是切实可行的．