EXPERIMENTAL RESEARCH INSIDE A GAS HEATER WITH DIFFERENT INTERMEDIATE HEAT CARRIER MEDIUM
The gas heater is one of the key equipments in gas industry, which plays the role of heating natural gas to the required processing temperature, and the application of gas heater shows a promising prospect. The cylindertype heating device with an intermediate heat carrier medium is most widely employed. Apparently, the selection of intermediate heat carrier medium and the form of heat transfer process of the intermediate heat carrier medium, i.e. the flow field organization in the large capacity cylinder, is the key elements that greatly affect the thermal efficiency of gas heater. A real gas heater experimental system, which is the only one in China, is built. The present paper characterizes water and ethylene glycol as the intermediate heat carrier medium. Experimental measurements and analysis on the flow condition and temperature distribution between the water and ethylene glycol in the cylinder were carried out. The results shown that using ethylene glycol as the heat carrier media can widen the application range of gas heater. The efficiency of the heater with ethylene glycol as the heat carrier medium is at least 3.8% higher than that with water as the heat carrier medium under the same working conditions. The thermal efficiency of gas heater is usually less than 87%.
Structure and heat transfer analysis on natural gas heater
As a special type of heater,natural gas heater is indispensable equipment in natural gas application system.According to the structure of natural gas heater,its heating surface and cooling surface are all eccentrically-oriented.The mathematic analysis of natural convection in eccentric cylinder was conducted,the medium flow and temperature field were numerically simulated in the bipolar coordinate system.The result indicates that the flow and heat transfer would perform the best when the heating surface is in the lower half of the cylinder.
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.