Introduction of a Supercritical Kerosene Test Bench Based on One-Stage Electric Heater with Large Current
A kind of supercritical kerosene heat transfer test bench was introduced in this article. It uses large current to heat the stainless steel tube directly and then the kerosene flowing inside the tube can be heated. A kind of needle valve is used to adjust the kerosene mass flow rate and a kind of backpressure valve is used to adjust the pressure inside the test tube. Insulating materials are laid at the two sides of the tube to prevent electrical leakage. Heat flux is calculated by measurements of the voltage and current. Kerosene is rapidly heated to high temperatures while the wall temperature is below the safety limit by increasing the tube length and thickness. The electric heater could effectively simulate the heat flux of a scramjet engine chamber with a maximum power of about 28KW. Kerosene within 15g/s could be quickly heated to 1000K with this system.
超临界煤油超声速燃烧特性实验 Experiments on Supersonic Combustion of Supercritical Kerosene
针对各种温度、压力下，马赫数2．5流场中超临界煤油的超声速燃烧性能进行了实验研究。研制并测试了一个新型二级煤油加热系统，该系统能够把0．8kg的煤油在5．5MPa压力下加热至至950K而不产生严重的结碳。超声速燃烧试验表明，在相同的来流和燃料当量比条件下，超临界煤油的燃烧效率比室温煤油提高10％～15％，与氢气泡雾化的燃烧效率相当。
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.