化工原理（1）（全英文）章节测试课后答案2024春

第二章测试

1.In a Hagen-Poiseuille flow, i.e. laminar pressure-driven flow in a circular pipe, if the pressure drop is doubled, the average and maximum velocities will _____. 在哈根-泊谡叶流中，当压降变为原来的两倍时，流体的平均和最大速度会_____。( )
A:remain constant 保持不变 B:both become four times均变为原来4倍 C:both double 均变为原来2倍 D:average velocity will double, while maximum velocity will become four times as large 平均速度变为2倍，最大速度变为4倍 E:average velocity will quadruple, while maximum velocity will double平均速度变为4倍，最大速度变为2倍
答案:C
2.Boundary layer occurs in _____. 边界层存在于_____。( )
A:laminar, transitional and turbulent flows 层流、湍流和过渡流中 B:turbulent flow only仅存在于湍流中 C:transitional and turbulent flows only 仅存在于过渡流和湍流中 D:laminar flow only 仅存在于层流中 E:transitional flow only仅存在于过渡流中 3.The continuum hypothesis of fluid mechanics assumes that fluid can be _____. 流体力学的连续性假设是说，流体可以_____。( )
A:subject to thermal fluctuations 受到热扰动的影响 B:divided infinitely 被无限划分 C:divided into molecules and atoms 被划分为分子和原子 D:none of the rest 其他都不对 E:gas or liquid 是气体或液体 4.A fluid flow may be laminar, turbulent or transitional, depending on its _____. 流体流动究竟是层流、过渡流还是湍流，取决于_____。( )
A:Froude number 福禄数 B:Bernoulli number 柏努利数 C:Reynolds number 雷诺数 D:none of the rest 其他均不对 E:Prandtl number 普朗特数 5.To solve for the velocity distribution of a viscous flow, we should use _____. 对于黏性流体，欲求得其速度分布，应该采用_____。( )
A:Navier-Stokes equation 奈维-斯托克斯方程 B:Bernoulli equation 柏努利方程 C:Euler equation 欧拉方程 D:Darcy-Weisbach equation 达西-瓦斯巴赫方程 E:Colebrook-White equation 科尔布鲁克-怀特方程 6.A liquid flows from a pipe of diameter into a pipe of diameter . The minor loss coefficient is _____. 某液体从直径为D的管道流入直径为2D的管道，其局部阻力系数K是 _____. ( )
A:9/16 B:3/4 C:none of the rest 其他均不对 D:1/4 E:1/2 7.A liquid flow is first divided into three separate pipe flows and later they merge into a single stream again. In this process, the total head loss is _____. 某股液流先分为三股，随后又汇为一股。在此过程中，总压头损失为_____. ( )
A:1/3 of the initial total head 原总压头的1/3 B:none of the rest 其他均不对 C:zero 零 D:half of the initial total head 原总压头的一半 E:the sum of head losses in all three pipes 三个分支管路中压头损失之和