Dataset of On-tube local condensation heat transfer coefficient of R134a, R513A and R450A on smooth stainless-steel tube at saturation temperature of 35 and 40℃

These data contain local condensation heat transfer coefficients of three refrigerants (i.e., R134a, R4513A and R450A) on a single, horizontal, smooth stainless tube at saturation temperatures of 35 and 40℃. A custom experimental apparatus was constructed to measure on-tube condensation heat transfer coefficients which consisted of two main parts, the chamber and the condensation tube. Refrigerant was vaporized in the experimental chamber and then condensed on the condensation tube. Two recirculating chillers were connected to the experimental chamber. One supplied cooling water through the condensation tube and the other supplied water used to boil the liquid refrigerant in order to achieve saturation temperatures of 35 or 40℃ . The refrigerant boiled and subsequently condensed on the smooth condensation tube. Thermocouples were installed in the flow to measure temperature at the inlet and outlet of the tube. The condensation tube was machined using electron discharge machining and 1.016-mm-diameter thermocouples(T1-T8) were installed in the tube wall in order to measure heat flux through the wall at two radial positions, β=11o from the vertical and β=109o from the vertical. Four thermocouples (T1-T4) were used to compute heat flux at β=11o, and an additional four thermocouples (T5-T8) were used to compute heat flux at β=109o.
Saturation pressures equivalent to 35 ± 0.5℃ and 40±0.5℃ were monitored in LabVIEW. Steady state was attained when the vapor pressure and temperature variation across the wall were in the range of ±0.34 kPa and ±0.05℃. After steady state was reached, experimental data were recorded for five minutes. Each experimental datapoint is the average of data collected within five minutes, and they include the eight thermocouple wall temperatures, mass flow rate of cooling water, temperature inlet and outlet of cooling water, saturation temperature and pressure of refrigerants. The outer wall temperature varied around the tube, and the measured wall temperatures were used to compute the outer wall temperatures and temperature gradients at radial positions around the tube using a natural logarithm curve fit with the measured wall temperatures as input. These values were used to compute heat fluxes and local heat transfer coefficients were computed using thermal conductivity, heat flux, saturation temperature (determined from the measured saturation pressure) and wall temperatures. Uncertainties of local heat transfer coefficients for each experimental trial were calculated using the propagation of uncertainty method and uncertainties of the instrumentation.

本数据集包含了三种制冷剂（即R134a、R4513A和R450A）在饱和温度为35℃和40℃时，于单根水平光滑不锈钢管上的局部沸腾传热系数。为测量管内沸腾传热系数，构建了一个定制实验装置，该装置主要由气室和冷凝管两部分组成。制冷剂在实验气室中蒸发，随后在冷凝管上冷凝。两个循环冷却器连接至实验气室，其中之一通过冷凝管供应冷却水，另一个则供应用于将液态制冷剂煮沸的水，以实现35℃或40℃的饱和温度。制冷剂在光滑的冷凝管上沸腾并随后冷凝。在流道中安装了热电偶以测量管进出口的温度。冷凝管采用电子放电加工制成，并在管壁上安装了直径为1.016毫米的热电偶（T1-T8），以测量两个径向位置（β=11°和β=109°相对于垂直方向）的壁面热通量。四个热电偶（T1-T4）用于计算β=11°处的热通量，另外四个热电偶（T5-T8）用于计算β=109°处的热通量。在LabVIEW中监测了相当于35±0.5℃和40±0.5℃的饱和压力。当蒸汽压力和壁面温度变化在±0.34 kPa和±0.05℃范围内时，系统达到稳态。稳态达到后，记录了五分钟的实验数据。每个实验数据点为五分钟内收集数据的平均值，包括八个热电偶的壁面温度、冷却水的质量流量、冷却水的进出口温度、制冷剂的饱和温度和压力。管外壁温度沿管周围变化，通过自然对数曲线拟合法，利用测量的壁面温度计算了管周围径向位置的外壁温度和温度梯度。这些值用于计算热通量，并利用热导率、热通量、饱和温度（由测量的饱和压力确定）和壁面温度计算局部传热系数。每个实验试验的局部传热系数的不确定性通过不确定性传播方法计算，仪器的不确定性也进行了评估。