Temperature efficiency relationship

Inereasing the pressure ratio and the turbine firing temperature inereases the Brayton cycle efficiency. This relationship of overall cycle efficiency is based on certain simplification assumptions such as (1) liia > nif, (2) the gas is caloricaly and thermally perfect, which means that... 

As alternatives to the isentropic efficiencies for the turbomachinery components, tjt and Tjc. which relate the overall enthalpy changes, small-stage or poly tropic efficiencies (Tjpj and Tjpc) are often used. The pressure-temperature relationship along an expansion line is then p T = constant, where z = [y y OtJpt]-... 

FIGURE 19.7 Radiant efficiency and relationship between voltage and temperature of various radiators. (Courtesy of Fostoria Industries, Inc., Fostoria, OH.)... 

The primal advantage of hierarchical databases is that the relationship between the data at the different levels is easy. The simplicity and efficiency of the data model is a great advantage of the hierarchical DBS. Large data sets (scries of measurements where the data values are dependent on different parameters such as boiling point, temperature, or pressure) could be implemented with an acceptable response time. 

The efficiency of an induction furnace installation is determined by the ratio of the load usehil power, P, to the input power P, drawn from the utihty. Losses that must be considered include those in the power converter (transformer, capacitors, frequency converter, etc), transmission lines, cod electrical losses, and thermal loss from the furnace. Figure 1 illustrates the relationships for an induction furnace operating at a constant load temperature with variable input power. Thermal losses are constant, cod losses are a constant percentage of the cod input power, and the usehd out power varies linearly once the fixed losses are satisfied. 

In the case of the actual cycle the effect of the turbine compressor (rjc), and expander (rjt) efficiencies must also be taken into account, to obtain the overall cycle efficiency between the firing temperature Tf and the ambient temperature Tamb of the turbine. This relationship is given in the following equation ... 

To obtain a more accurate relationship between the overall thermal efficiency and the inlet turbine temperatures, overall pressure ratios, and output work, consider the following relationships. For maximum overall thermal cycle efficiency, the following equation gives the optimum pressure ratio for fixed inlet temperatures and efficiencies to the compressor and turbine ... 

Power requirements and discharge temperatures are calculated using the same relationships as used with the other rotary compressors already discussed. The efficiency is. 80 for air service and pressure in the 30 psig range. The mechanical losses are higher than the other rotaries. The mechanical loss is variable and dependent on gas, lubrication, and other factors. For an estimate, use. 15 of the gas horsepower. This approxuna tion should be close enough for an estimate. 

Adsorption for gas purification comes under the category of dynamic adsorption. Where a high separation efficiency is required, the adsorption would be stopped when the breakthrough point is reached. The relationship between adsorbate concentration in the gas stream and the solid may be determined experimentally and plotted in the form of isotherms. These are usually determined under static equilibrium conditions but dynamic adsorption conditions operating in gas purification bear little relationship to these results. Isotherms indicate the affinity of the adsorbent for the adsorbate but do not relate the contact time or the amount of adsorbent required to reduce the adsorbate from one concentration to another. Factors which influence the service time of an adsorbent bed include the grain size of the adsorbent depth of adsorbent bed gas velocity temperature of gas and adsorbent pressure of the gas stream concentration of the adsorbates concentration of other gas constituents which may be adsorbed at the same time moisture content of the gas and adsorbent concentration of substances which may polymerize or react with the adsorbent adsorptive capacity of the adsorbent for the adsorbate over the concentration range applicable over the filter or carbon bed efficiency of adsorbate removal required. 

In the case of gaseous contaminants, the tracer gas is selected to simu late as well as possible the properties (density, temperature) and momentum of the real contaminant. It is essential to ensure that the tracers arc nontoxic, chemically nonreactive, nonadsorptive on indoor surfaces, and inexpensive. The mixing of the tracer with the actual gaseous contaminant before its release or the release of the tracer with a density near that of the air will improve the validity of the simulation. With tracers, the most difficult task in practice is the relationship of the discharge between the tracer and the real contaminant. Case-by-case techniques to release the tracer are necessary in practice. With tracer gases, the procedure for capture efficiency is described in detail in the European Standard. - The tracer gas concentrations are measured in the exhaust duct for two release locations as illustrated in Fig. 10.108. 

Many operating variables, such as sample volume, flow rate, column length, and temperature, must be considered when performing any separation. The relative importance of these variables for Toyopearl HW-55F resin columns has been specifically evaluated. For example. Fig. 4.47 shows the relationship between column efficiency, or height equivalent of a theoretical plate (HETP),... 

Some notes on FW and air temperature efficiency are given in the following list. A very simple guideline to the relationship between relative heat transfer surfaces compared with heat absorbed is shown in Table 1.3). 

Consider a process shown in Figure 2.14 in which a quantity of heat q2 flows from a high temperature reservoir T2 into a reversible cyclic engine. Part of the heat is converted into work ir while the remainder q flows into a low temperature reservoir. The efficiency of this process is defined asqq r) = -w/q2, and it is a function of the reservoir temperatures. The relationship can be derived as follows ... 

Fish show generally low HMO activities that are not strongly related to body weight. This may reflect a limited requirement of fish for metabolic detoxication they are able to efficiently excrete many compounds by diffusion across the gills. The weak relationship of HMO activity to body weight is probably because fish are poikilotherms and should not, therefore, have an energy requirement for the maintenance of body temperature that is a function of body size. In other words, the rate of intake of xenobiotics with food is unlikely to be strongly related to body size. 

The relationship between temperature and pressure holds true only in the presence of pure steam adulteration with air contributes to a partial pressure but not to the temperature of the steam. Thus, in the presence of air the temperature achieved will reflect the contribution made by the steam and will be lower than that normally attributed to the total pressure recorded. Addition of further steam will raise the temperature but residual air surrounding articles may delay heat penetration or, if a large amount of air is present, it may collect at the bottom of the sterilizer, completely altering the temperature profile of the sterilizer chamber. It is for these reasons that efficient air removal is a major aim in the design and operation of a boiler-fed steam sterilizer. 

The plate height, and thus the total number of theoretical or effective plates, depends on the average linear carrier gas velocity (van Deemter relationship) and, for a particular carrier gas, the efficiency will maximize at a particular flow rate. Only at the optimum carrier gas flow rate are n, N, and HETP Independent of the column length. The efficiency will also depend on the column diameter (see section 1.7.1) where typical values for n, N, and HETP for different column types can also be found. Values for n, N, and HETP are reasonably independent of temperature but may vary with the substance used for their determination, particularly if the test substance and statioKary phase are not compatible. 

In extraction from a polymer/additive solid matrix the rate-determining step in the extraction process is governed by the interaction of the solvent of sufficient dissolution power with the matrix and the removal of the analyte (cf. Section 3.4.1.3). There appears to exist a direct relationship between degree of swelling and efficiency of extraction. The amount of C02 absorbed depends on temperature, pressure and the polymer concerned. Crystalline polymers are-not surprisingly-plasticised less... 

Heat and mass balance equations are used in all aspects of process modelling however, what is key to this model is an understanding of the electrolytic process behind the cell. For example, the model must be able to predict current efficiency and k-factor if it is to predict electricity consumption. Most of these electrolytic parameters are calculated using empirical relationships derived from experimental data both from test cells and the full-scale plant. Considering k-factor, this is primarily a function of brine strength and temperature. Figure 20.5 illustrates the experimentally derived function used in the model. 

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