Stagnation temperature

Rice SF, McDaniel AH, Hecht ES, Hardy AJJ Methane partial oxidation catalyzed by platinum and rhodium in a high-temperature stagnation flow reactor, Ind Eng Chem Res 46 1114-1119, 2007. 

Total temperature is the temperature that would occur when the fluid is brought to rest in a reversible adiabatic manner. Just like its co mie p2L totalpressure, total eMd stagnation temperatures are used interchangeably by many test engineers. 

Inlet and diseharge temperatures are the stagnation temperatures at the respeetive points and should be measured within an aeeuraey of 1 °F (0.55 °C). When the veloeity of the gas stream is more than 125 fps (36.6 mps), the veloeity effeet should be ineluded in the temperature measurement with a total temperature probe. This probe is a thermoeouple with its hot junetion provided with a shielded eup. The eup opening points upstream. A trade-off has to be made in a field test situation where the gas is not elean. 

That the compound is not allowed to stagnate in heated zones of the extruder and thus decompose. The life of many compounds at processing temperatures is little more than the normal residence time of the material in the extruder. 

From (a) and (b), the stagnation pressure and temperature can thus be calculated at exit from the cooled row they can then be used to study the flow through the next (rotor) row. From there on a similar procedure may be followed (for a rotating row the relative (7 o)r, i and (po)k replace the absolute stagnation properties). In this way, the work output from the complete cooled turbine can be obtained for use within the cycle calculation, given the cooling quantities ip. 

Change in stagnation enthalpy (or temperature) through an open cooled blade row... 

A more sophisticated approach would not only take account of Eqs. (4.45) and (4.46) to give the two stagnation temperatures at exit from control surfaces A and B, but it would also not assume the total pressures of coolant and mainstream to be the same. Eor the first nozzle guide vane row these can be derived by accounting for losses as follows ... 

In design considerations for Thermonized process lines, temperatures may be determined by the Stagnation Method. The calculations involved in this method are based on static conditions where process fluid flow is not present, and are independent of the viscosity, density and thermal conductivity of the process fluid. The process temperature may be calculated from the following relationship ... 

Two-dimensional compressible momentum and energy equations were solved by Asako and Toriyama (2005) to obtain the heat transfer characteristics of gaseous flows in parallel-plate micro-channels. The problem is modeled as a parallel-plate channel, as shown in Fig. 4.19, with a chamber at the stagnation temperature Tstg and the stagnation pressure T stg attached to its upstream section. The flow is assumed to be steady, two-dimensional, and laminar. The fluid is assumed to be an ideal gas. The computations were performed to obtain the adiabatic wall temperature and also to obtain the total temperature of channels with the isothermal walls. The governing equations can be expressed as... 

A CSTR is a deliberately backmixed reactor and, in principle, its effluent temperature and composition are the same as the reactor contents. With an ideal CSTR, the feed blends instantaneously with the uniform reactor contents. In actual practice, of course, we find that feed blending time may be protracted, and varying degrees of segregation, short circuiting and stagnation exist in the reactor contents. 

PIV velocity measurements made it possible to evaluate the flame temperature field [23], following the method demonstrated in Ref. [25]. The calculated thermal structure of lean limit methane flame is shown in Figure 3.1.7. The differences between the structures of lean limit methane and propane flames are fundamental. The most striking phenomenon seen from Figure 3.1.7 is the low temperature in the stagnation zone (the calculated temperatures near the tube axis seem unrealistically low, probably due to very low gas velocities in the stagnation core). 

The zoogeographic history of the Japan Sea proposed by Chinzei (1991) (Fig. 4.5 and Fig. 4.6) indicated that (1) from 17 to 15 Ma, before the spreading of the Japan Sea, tropical and subtropical molluscs invaded the area (2) the benthic and planktonic faunas changed sharply into low temperature faunas at about 15 Ma (3) from about 10 to 5 Ma, sedimentary deposits formed that were barren of benthic molluscs as a result of the stagnation of the Japan Sea basin (4) cold-water molluscan fauna reappeared in the coastal areas at about 5 Ma and (5) this has been followed by a period of marked cyclicity of cold and warm water faunas since about 1.3 Ma. 

An estimate of the temperature of the clusters in the reactor tube can be obtained from the velocity of the atomic species in the beam. This velocity, assuming insignificant slippage, is related to the "stagnation" temperature by( 18)... 

The temperature T0 corresponding to zero velocity is known as the adiabatic stagnation temperature it is the temperature that the flowing gas would attain if it were brought to rest adiabatically without doing any shaft work. It is sometimes called the total temperature. The temperature difference is small for air flowing at a speed of 100 m/s, T0 - T = 5 K. 

When a thermometer is placed in a flowing gas stream, most of the thermometer s surface has gas flowing past it but a stagnation point occurs at its upstream side. Thus instead of measuring the temperature T, it measures a value that is slightly higher. This can be accommodated by introducing a correction factor known as the recovery factor r/. 

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