多联式空调室外机翅片管换热器仿真设计

本文结合多联机空调的实际运行状态与工作环境,分别探讨了翅片间距,翅片形式以及翅片管长度等在制冷和制暖条件下对换热量的影响。计算结果表明,开窗波纹片、开窗平片、平片的换热能力依次降低,翅片密度的增加可以增强换热效果。随着数量增加其增强效果逐渐减弱,翅片密度的增大会使热交换器的空气侧压降显著增大,热交换器制冷剂管路横向间距的增大、纵向间距的减小对换热性能有改善作用。

直升机滑油散热器动态性能分析

滑油散热器的动态特性是直升机滑油冷却系统设计的基础,使用模块化集总参数法建立了直升机滑油散热器的动态仿真模型,采用Laplace变换建立动态传递函数,结合动态仿真模拟曲线的比较以及传递函数的分析,对热侧和冷侧入口温度阶跃变化时的热侧出口温度动态响应性能进行分析,得到了影响动态性能的重要影响参数——芯体蓄热时间常数τw以及热侧温度随流动时间τ变化的时间常数hτ,从而可通过改变这两个重要影响参数来有效改变散热器以及系统的动态延迟时间.通过散热器动态实验测量,验证了模型的正确性.研究成果可有效改进散热器以及系统的动态性能,以及指导散热器与系统的优化耦合设计.

风机盘管的质量控制

本文介绍了如何控制风机盘管的质量。

Experimental investigation of enhanced heat transfer for fined circular tube heat exchanger with rectangular fins

Presents a set of data for flow and heat transfer of finned-tube bundle under the condition of high air flow velocity. Air flow and heat transfer over a 4 × 4 （ columns × rows） finned-tube heat exchanger with rectangular fins was investigated experimentally in a wind tunnel with constant wall temperatures condition. The air flow velocity based on the minimum flow cross-section area over flow channel ranged from 13.8 to 50. 2 m/s, the heal transfer rate ranged from 21.8 to47. 1 kW, and the air temperatures increase ranged from 10. 9 to 19. 8 ℃. The present results were compared with results calculated from correlations proposed by CSPE. For air flow velocity less than 25 m/s, these two results of heat transfer agreed well with each other, whereas for larger velocity, our test data disagreed with the CSPE correlations. For the friction factor, present data are much higher than the predicted results in the whole range. Finally, correlations for friction factors and heat transfer coefficients are DrODosed based on the experimental results.

浅析PLC在空调中的应用

可编程逻辑控制器,即PLC,因自身编程方便、配置灵活和较高的可靠性故而被广泛应用于现代工业控制当中,特别是在相对恶劣的工作环境中,PLC对设备系统的控制具有较高的效率。基于此,以PLC在空调中的应用作为主要研究内容,通过对PLC的相关概念进行阐述和分析,进而分别对PLC在空调交换器自动翅片机与节能系统中的应用展开了深入研究。