单流束旋翼式户用热量表的性能研究

【作者】 刘立宁；

【导师】 杜广生；

【作者基本信息】 山东大学 ， 热能工程， 2006， 硕士

【摘要】 目前我国正在进行供热体制改革，对热量表的需求量极大，但国产热量表的技术水平还相当低，测试精度和可靠性与国外产品相比还有相当大的差距。如何提高国产热量表的自主开发能力，还有待于理论的指导和研究。本研究对适应我国国情的单流束旋翼式户用热量表的性能进行了研究，给出了相关的研究结果，对热量表的设计及安装具有一定的指导意义。 本文主要采用了理论分析、数值模拟及实验研究的方法，其中，理论分析渗透于数值模拟及实验过程中，并对计算和实验起指导和补充作用。借鉴已有的旋转机械的数值模拟经验，应用计算流体力学软件，对单流束旋翼式热量表的内部流场进行了三维数值模拟。根据模拟结果分析叶轮的受力情况以及流动参数、基表内部的关键部件对表内流动的影响，找出相关规律。最后，通过实验及理论分析来验证数值模拟的计算结果。经过综合分析，给出热量表设计安装过程中的相关准则及注意事项。 本研究中所使用的单流束旋翼式户用热量表采用的是无磁式信号采集方式，通过对脉冲信号的测量，测得流量信号。通过对测量的瞬时流量和温度进行积分，得到所测量的热量值。研究结果表明，介质的温度变化对热量表的稳定性影响较小，在一定的误差范围内可以认为热量表的脉冲当量为一定值，不随温度的变化而变化。调整叶轮室上盖下方的调节肋板的角度，可以改变水流对叶轮旋转的阻尼作用的大小，从而改变叶轮的旋转速度，最终影响热量表脉冲信号的测量精度。叶轮的叶片数对脉冲当量也有一定的影响，叶片数太少，叶轮转速过慢：而叶片数增多，对增加脉冲当量有一定的效果，但不宜太多。模拟计算和实验的结果表明，比较合理的叶片数为6片或者7片。另外，在热量表的安装过程中表前需安装一些控制阀及调节阀等，这些局部件的存在，会对热量表的测量精度产生影响，为消除这些扰动的影响，需在热量表前安装适当长度的直管段。通过数值模拟计算及实验研究知，当表前直管段长度≥4倍的管径长度时，足可以保证热量表的测量精度。本文对以上各影响因素进行了详细的分析。热量表内部小尺寸的改变，对其测试精度也会有一定的影响，文中进行了简略分析。另外，模拟计算及实验结果均表明基表前后的压强损失与流量的平方成正比关系。更多还原

【Abstract】 The demand for heat meter is great in our country at present because of the heat supply system innovation. Compared to foreign products, the technological level of the domestic heat meter is still quite low, especially in the aspect of precision and dependability. How to improve the ability of developing independently is still an issue. This paper provides relevant results of research and has certain directive significance on designing and installation of the heat meter after researching the performance of flow bunches of rotor type household which is proper for the national situation of our country.Methods mainly adopted in this text include: theory analysis, numerical simulation and experiment, among them, theory analysis play a guidance and supplement role for the calculation and experiment. Meanwhile, theory analysis permeate in the process of numerical simulation and experiment, to calculate and experiment. Based on the existing numerical simulation experience of rotator machinery for reference, three-dimensional value simulation was made to single-channel flow heat meter with applying the hydro-mechanical software. Then find out the relevant principles after analyzing impeller situation and flow parameter, influence of key part on flowing according to the results of simulation. Finally, verifies the result of calculation of the numerical simulation through experiment and theory research. Through comprehensive analysis, the relevant criteria and attentive matters about heat meter design and installation can be providedWhom research this use flow bunches of rotor household whom form adopt to have magnetism type signal gather the way with heat only, through to the measurement of the pulse signal, measure the flow signal. Through carrying on the total mark to instantaneous flow and temperature measured, get the heat value measured. The result of research indicates the temperature change of the medium has a little effect on stability of the heat meter. So within the range of certain error the pulse equivalent of the heat meter will be a fixed value, do not vary with temperature. By adjusting the angle of regulation rib under the top cover of impeller room, we can change the influence to whirling of impeller by stream, then in turn更多还原