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Boilers
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Natural-circulation boilers depend on the difference in fluid density to drive circulation. Cold water is forced to the bottom of the boiler and hotter water or steam-water mixtures to the top and into the steam separation drum. Forced circulation boilers use pumps to force water to flow through the tubes. These are commonly used when space limitations require a more compact design, or when tubes must be placed horizontally rather than vertically. Because forced circulation units can include subdivisions of pressure parts, they can be used to handle large capacities and high pressures. Figure 7-17 provides elevation and plan view illustrations of convection tubes in an industrial watertube boiler.
Study on thermal parameters of asphalt concrete for countermeasures against high surface temperature of pavement in tunnel
Published in Road Materials and Pavement Design, 2021
Aibek Toktorbai uulu, Hiroshi Katsuchi, Haeyoung Kim, Hitoshi Yamada, Yusuke Ijima
An open circuit wind-tunnel with a unique test facility of Yokohama National University (YNU) was used to measure the thermal characteristics for various types of AC specimens. Figure 2 shows the general view and the working section of the wind-tunnel. The size of the working section is 1.3 m wide and 1.3 m high. A forced circulation boiler system is shown in Figure 3. A detailed scheme of the experimental procedure is depicted in Figure 4. The system comprises a heated water flow loop and a fixed asphalt specimen for the test. Pump power causes the water to circulate in the pipe that passes through the boiler and the heat exchanger. Then, the air inside the wind-tunnel is heated. The temperature of the heated air can be adjusted by the temperature controller.