Ceramic manifolds

Two types (type A and B) of micro SOFC stacks were prepared as shown in Fig, 2 using those micro tubular SOFC bundles. The type A was constructed using four micro bundles with. 8 mm tubes, vertically connected in series after applying sealing layer and interconnects to each bundle. Fuel and air were applied using ceramic manifolds as shown in Fig. 2 (a). The type B consists of three bundles, sealing layers and interconnects, and fuel manifolds. The size of the stack A without fuel manifold is I x I x 0.8 cm ( 0.8 cm ) and the size of the stack B without fuel manifold is 1 x 3 cm with tlie thickness of 3.3 mm ( 1 cm ). 

The stack assembly includes ceramic manifold components not further specified, metallic interconnect compounds, and glass ceramics for sealing and joining. The main components are silicon dioxide, calcium oxide, aluminum oxide, and barium oxide. 

Cascade coolers are a series of standard pipes, usually manifolded in parallel, and connected in series by vertically or horizontally oriented U-bends. Process fluid flows inside the pipe entering at the bottom and water trickles from the top downward over the external pipe surface. The water is collected from a trough under the pipe sections, cooled, and recirculated over the pipe sections. The pipe material can be any of the metallic and also glass, impeiMous graphite, and ceramics. The tubeside coefficient and pressure drop is as in any circular duct. The water coefficient (with Re number less than 2100) is calculated from the following equation by W.H. McAdams, TB. Drew, and G.S. Bays Jr., from the ASME trans. 62, 627-631 (1940). 

Manifold barriers confine the radioactivity to the 1) ceramic fuel pellet 2) clad 3) cooling water, as demonstrated by the TMI-2 accident 4) primary cooling loop 5) containment and 6) separation from the public by siting. Further protection is provided by engineered safety systems pressurizers, depressurization, low pressure injection, high pressure injection and residmil heat removal systems. 

Naturally, fibers and whiskers are of little use unless they are bonded together to take the form of a structural element that can carry loads. The binder material is usually called a matrix (not to be confused with the mathematical concept of a matrix). The purpose of the matrix is manifold support of the fibers or whiskers, protection of the fibers or whiskers, stress transfer between broken fibers or whiskers, etc. Typically, the matrix is of considerably lower density, stiffness, and strength than the fibers or whiskers. However, the combination of fibers or whiskers and a matrix can have very high strength and stiffness, yet still have low density. Matrix materials can be polymers, metals, ceramics, or carbon. The cost of each matrix escalates in that order as does the temperature resistance. 

For many applications, like chemical-vapor-deposition reactors, the semi-infinite outer flow is not an appropriate model. Reactors are often designed so that the incoming flow issues through a physical manifold that is parallel to the stagnation surface and separated by a fixed distance. Typically the manifolds (also called showerheads) are designed so that the axial velocity u is uniform, that is, independent of the radial position. Moreover, since the manifold is a solid material, the radial velocity at the manifold face is zero, due to the no-slip condition. One way to fabricate a showerhead manifold is to drill many small holes in a plate, thus causing a large pressure drop across the manifold relative to the pressure variations in the plenum upstream of the manifold and the reactor downstream of the manifold. A porous metal or ceramic plate would provide another way to fabricate the manifold. 

Converters now in use contain noble metals on a ceramic substrate (e.g., platinum dispersed on alumina). The convener is typically located in the exhaust system in one of two general locations an underfloor location, or a close-coupled location near (he manifold. The operating temperature range lor noble metal catalyst is from 600 In I200 F (316 lo 649 C). which is similar to the exhaust pipe skin temperature range normally encountered or standard automobile engines. 

In conclusion, it can be stated that Si3N4 ceramics are polyphased materials including mainly /fss, ass, secondary phases (mainly oxide nitrides, in ceramic literature generally called oxynitrides) and an amorphous phase, all having characteristic morphologies and can be arranged in a manifold of microstructures (Sect. 6). 

The term foam is defined as a gaseous void surrounded by a much denser continuous matrix, generally a liquid or a solid phase. As a result of the distinct characteristics of the two phases, such cellular materials are able to feature unique properties. Since nature successfully demonstrated their use in manifold examples, such as bones, wood, plant stalks, cork, and sponges, foams have also sparked interest for technical application. Nowadays, a broad range of cellular materials based on metals, ceramics as well as polymers, is readily available, and their structures are as versatile as their applications. 

Figure 1. The MHHP modular sorber diagram 1 - tubular case of the hydride module 2 -corrugated heat-conducting insert 3 - hydrogen ceramic collector-filter 4 - metal hydride 5 - tip of a metal hydride bed 6 - hydrogen manifold 7 - spacer plate 8 - heat exchanger shroud 9 - union 10 - flange-cover of a heat exchanger. Heat exchanger thermal insulation is not shown conditionally.

Figure 2. The MHHP monoblock sorber diagram 1 - case of a sorber 2 - heat exchanging tube 3 - heat-conducting edges 4 - metal hydride 5 - tube with metal hydride bed 6 -ceramic hydrogen collector-filter 7-hydrogen manifold 8 - casing of a heat exchanger 9 -union. Thermal insulation of a heat exchanger is not shown conditionally.

Preparative organosilicon chemistry offers manifold possibilities for the synthesis of precursors for nonoxide ceramics (Scheme 18.1). The focus has been on the synthesis of polymers such as polysilanes A, polysilazanes B, polycarbosilanes... 

It is a good practice to place a filtering device (ceramic or synthetic material) between the solution to be pumped and the sampling tube to prevent the influx of particulate matter into the manifold. 

The DieMate manifold is insulated to improve thermal uniformity and to prevent exposure of the DieMate socket to excess temperature. (The DieMate socket maximum temperature specihcation is 150 °C.) Figure 12.4 shows the insulated DieMate manifold before attachment of the 1 /16-inch transfer lines. The insulation consists of a ceramic hber strip that has a maximum operating temperature of 2300 °F (1260° C). 

A flexible Kapton -coated heater is wrapped aroimd the clamshell and is powered using a 24 VDC input. The temperature of the clamshell is monitored using two 100 O platinum Resistive Temperature Devices (RTD s). Both the DieMate manifold and the clamshell heater are insulated using ceramic fiber strip obtained from a commercial source with a maximum temperature rating of 2300 F. 

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