Cooling channels

The efficiency of gas turbines is limited by the maximum allowable turbine inlet temperature (TIT). The TIT may be increased by cooling of the blades and vanes of the high pressure turbine. Cooling channels can be casted into the components or may be drilled afterwards. Non-conventional processes like EDM, ECD or Laser are used for drilling. Radiographic examination of the drilled components is part of the inspection procedure. Traditional X-Ray film technique has been used. The consumable costs, the waste disposal and the limited capacity of the two film units lead to the decision to investigate the alternative of Real-Time X-Ray. 

It is also possible to estimate the number of cooling channels required. If the thermal conductivity of the mould material is K then the heat removed through the mould per unit time will be given by... 

This is usually taken as half the circumference of the cooling channel multiplied by its length. 

The K value for steel is 11.5 cal/m.s.°C, so assuming that the cooling channels have a diameter of 10 mm and they are placed 40 mm from the cavity, then... 

If the length of the cavity is 130 mm then five cooling channels would be needed to provide the necessary heat removal. 

Production molds are usually made from steel for pressure molding that requires heating or cooling channels, strength to resist the forming forces, and/or wear resistance to withstand the wear due to plastic melts, particularly that which has glass and other abrasive fillers. However most blow molds are cast or machined from aluminum, beryllium copper, zinc, or Kirksite due to their fast heat transfer characteristics. But where they require extra performances steel is used. 

Platelet No. 1 material Aluminum, anodically oxidized Cooling channel No. 4 diameter length 300 pm 6.5 mm... 

Reactor type Multi-channel integrated mixer-heat exchanger Hydraulic diameter of cooling channel 900 pm... 

Hydraulic diameter of reaction channel 200 pm Thickness of wall separating reaction and cooling channels 1 mm... 

Micro reaction channels can be operated in tight contact with cooling channels so that large reaction heats can be removed. By this means, formerly uncontrollable reaction conditions may be realized. 

Top plate thickness 4 mm Cooling channel 2.5 mm internal diameter... 

The simplest molds consist of two parts one fixed and one moveable. We use such molds to fabricate items, such as disposable stadium cups, compact disks, and coat hangers, which have simple designs with no undercuts. As the complexity of the product increases, so must the complexity of the mold. The molds used to produce large items, such as dishwasher tubs and automobile bumpers, may consist of multiple moveable components and weigh several tons. Even apparently simple items, such as screw tops for bottles, require a complex ejection system that unscrews the product from part of the mold. In order to facilitate cooling, virtually all molds are designed with liquid cooling channels. 

Large amounts of energy are consumed during the mixing process and this gives rise to large temperature rises in the rubber batch. Internal mixers therefore have cooling channels in the chamber walls, rotors, and sometimes the ram head, to dissipate this heat. The inlet water temperature is controlled in most modem machines, but in many companies this is still not the case. 

Channel Black Also called Gas Black. One of the processes used to make carbon black the others are the Acetylene Black, Fumace Black, Thermal Black, and Thermatomic processes. In the Channel Black process, natural gas was incompletely burnt in small flames, which impinged on cooled channel irons that were continuously moved and scraped. Invented by L. J. McNutt in 1892 and commercialized that year in Gallagher, PA. The last United States plant was closed in 1976. 

Forced gas cooling channel Quartz process tube... 

The surface trough was made of Lucite, 45 X 15 X 1.5 cm. and was divided into two compartments of equal size by a septum of Lucite, 1.5 cm. high. Cooling channels for temperature control were milled into the bottom of the trough. The monolayer was spread inside a paraffined mica frame which floated on the water and was firmly positioned by external mounts. The surface tension was measured with a double-hook torsion balance and a sand-blasted platinum Wilhemy plate. A Beckman model G pH meter with standard glass and KC1 electrodes was used to measure pH. 

Convective heat transfer to the ambient is enhanced by (1) increasing the heat-transfer area through the use of fins or cooling channels, (2) increasing the heat-transfer coefficient, or (3) reducing the temperature of the... 

The cooling channels in a metal block which is held at a uniform temperature of S0°C have a rectangular cross-sectional shape with a width of 6 mm and a height of 2 mm. Air at an initial temperature of 10°C flows through these channels at a mean velocity of 1.5 m/s. The block has a length of 22 cm in the flow direction. Find the heat transfer rate to the air in one channel. Assume fully developed laminar flow. 

The best molds are made of aluminum with water-cooling channels cut into them. Tooling costs are low, and heat transfer is high. The formed plastic sheet must be held against the mold surface until it is cooled to the solid state. This is often judged by the heat deflection temperature at 455 kPa (66 psi). 

The energy released shifted the l(XX)-tonne cover plate of the reactor, cutting all the cooling channels on both sides of the reactor cover. After two or three seconds, another explosion occurred, and hot pieces of the reactor were ejected from the damaged reactor building. The damage to the reactor permitted the influx of air, which then caused the graphite to bum. 

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