新型高温真空集热管端部热损失的实验研究与分析

EXPERIMENTAL STUDY AND ANALYSIS ON END HEAT LOSS OF A NEW HIGH TEMPERATURE VACUUM SOLAR RECEIVER

建立了真空集热管端部热损失的两种实验评估方法,研究表明端部覆盖时的热损失曲线明显低于端部暴露实验,并更接近一维模型的理论曲线。吸收管温度约300℃时,暴露端部的热损失约为200W,造成24.77%的额外热损失,覆盖端部的额外热损失仅为7.24%,且端部暴露时热损失对风速敏感。总的来说,集热管的热损失测试应在端部覆盖的情况下进行,以得到精确的热损失曲线;在实际运行中,集热管的端部也必须有保温材料完全包裹,以避免额外的热损失。

Two experimental methods were established to evaluate receiver＇s end heat loss. Research has shown the heat loss of end covered test is obviously lower than that of end exposure test, which is more close to 1-D evaluation. When absorber temperature is around 300℃, exposed end heat loss is approximately 200W, causing a 24.77 % extra heat loss, while the covered end cause only 7.24%. Moreover, exposed end heat loss is more sensitive to wind. In sum, receiver＇s thermal test should be conducted with end covered to acquire an accurate heat loss curve; and in the real operation the recever＇ s end should be completely covered by heat insulator to avoild extra heat loss.