Flow measurements total temperature

Firing temperature The mass-flow mean total temperature of the working fluid measured in a plane immediately upstream of the first-stage turbine buckets. 

Since this temperature requires the thermometer or thermocouple to be at rest relative to the flowing fluid, it is impractical to measure. It can be, however, calculated from the measurement of total temperature and total and static pressure. 

The measurement of an enthalpy change is based either on the law of conservation of energy or on the Newton and Stefan-Boltzmann laws for the rate of heat transfer. In the latter case, the heat flow between a sample and a heat sink maintained at isothermal conditions is measured. Most of these isoperibol heat flux calorimeters are of the twin type with two sample chambers, each surrounded by a thermopile linking it to a constant temperature metal block or another type of heat reservoir. A reaction is initiated in one sample chamber after obtaining a stable stationary state defining the baseline from the thermopiles. The other sample chamber acts as a reference. As the reaction proceeds, the thermopile measures the temperature difference between the sample chamber and the reference cell. The rate of heat flow between the calorimeter and its surroundings is proportional to the temperature difference between the sample and the heat sink and the total heat effect is proportional to the integrated area under the calorimetric peak. A calibration is thus... 

Unmeasured temperatures or concentrations that correspond to enthalpy or component flows in Vd are determinable if the total flow rate of the stream is measured. Otherwise, they are indeterminable. Measured total flow rates are nonredundant and unmeasured total flow rates are indeterminable. The analysis of intensive constraints between variables may change previous classification. 

Barolo et al. (1998) developed a mathematical model of a pilot-plant MVC column. The model was validated using experimental data on a highly non-ideal mixture (ethanol-water). The pilot plant and some of the operating constraints are described in Table 4.13. The column is equipped with a steam-heated thermosiphon reboiler, and a water-cooled total condenser (with subcooling of the condensate). Electropneumatic valves are installed in the process and steam lines. All flows are measured on a volumetric basis the steam flow measurement is pressure- and temperature-compensated, so that a mass flow measurement is available indirectly. Temperature measurements from several trays along the column are also available. The plant is interfaced to a personal computer, which performs data acquisition and logging, control routine calculation, and direct valve manipulation. 

The proposed modeling approach has been validated for distillation of non-reactive mixtures. For this purpose, the use is made of the total reflux distillation data for the binary mixture chlorobenzene/ethylbenzene (CB/EB) and ternary mixture methanol/acetonitrile/water (MEOH/ACN/WATER) obtained by Pelkonen (1997) as well as for the ternary mixture methanol/ethanol/water (MeOH/EtOH/WATER) measured by Mori et al. (2006). The experiments of Pelkonen (1997) were carried out in a column of 100 mm diameter, equipped with Montz-Pak A3-500 structured packing. The measured concentrations, temperature and flow rates at the condenser outlet are used as input values for simulations. 

Two thermocouples separated by distance L are imbedded in the test specimen, one directly above the other, whereby the temperature drop T2 — T between them is measured. A differential thermocouple measures the temperature rise ATw of the exit water of the calorimeter as compared to its entrance temperature. The mass flow rate of water F into the calorimeter is monitored, so that over a specific time interval At, the total heat absorbed by the calorimeter may be calculated, knowing the specific heat cp of water. Dividing by the time interval will give the rate of heat flow into the calorimeter under steady state conditions ... 

Fig. 2 shows a horizontal cross-section through NGFs coupled shear flow test (CSFT) cell. This biaxial cell allows fractured samples (14 x 12 x 5 cm) to be displaced by a maximum 8 mm under controlled fracture normal stresses and temperatures up to 80°C. Variation in fracture aperture (dilation) is measured by a total of four displacement gages, whereas shear displacement is measured by a total of two gages. The flow measurements, as illustrated in Fig. 2, measure the total flow in the direction of the fracture plane and do not differentiate between fracture and matrix flow. To quantify the matrix flow component, tests on non-fractured samples with the same principal geometry as the fractured tests and under the same stress conditions, were conducted in the CSFT cell. 

There are three main reasons for using inferential measurement of a controlled variable (1) Excessive analyzer deadtime undermines the performance of the feedback loop. (2) The total cost (i.e., the purchase price and maintenance cost) of an on-line analyzer can be excessive. Since inferential measurements are typically based on temperature, pressure, and flow measurements, they are much less expensive to install and maintain. (3) An on-line analyzer may not be available. In that case, an inferential measurement may be the only option for feedback control. 

During testing in the glass furnace environment, the detector assembly was cooled using a vortex tube cooler, with an adjustable air flow rate, in order to minimize the temperature excursions. Additionally, the temperature of the detector assembly was measured and documented for later use in data reduction. A statistical analysis of all calibration data including the temperature dependence of the detectors reveals an estimated uncertainty in measured temperature of +2% of the total measured absolute temperature. 

Figure 15.2 (a) The thermal conductivity of a material is the heat flow from a hot to a cold region. The temperature gradient between the hot and cold ends is a measure of the thermal conductivity of the material, (h) The temperature drop across a series of different materials will vary with the thermal conductivity of each, although the total temperature drop is the same. Note Q, heat transferred A, cross-sectional area... 

The liquid-nitrogen flow rate was measured with a turbine flowmeter. The total pressure of the jet exhaust Ptj was measured at an orifice in the model plenum chamber by a Precision Pressure Balance transducer. The total temperature of the CO2 exhaust was measured by a thermocouple in the line leading into the vacuum chamber. This thermocouple was downstream of the pressure-regulating valve and therefore measured the total temperature of the CO2 after the expansion to near the jet total pressure. The total temperature and the total pressure of the jet were used in a one-dimensional isentropic flow equation for choked nozzles to calculate the mass flow of CO2. The specific heat ratio used was that corresponding to the total temperature and pressure of the jet. 

A Mcttler II thermal analyzer was used in the work by Krien cited throughout this chapter. Other measurement conditions were as follows heating rate 6°Cmin DTA sensitivity 100 mV (total deflection) PtRh-Pt thermocouples used to measure the temperature, range 2 gV (full-scale) aluminum crucible, open reference material -Al20v dynamic dry air, flow-rate ca 97 ml min (5.8 1 h ). 

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