Calculation temperature rise

In ventilation systems the temperature rise calculated on the basis of specific heat alone will be pessimistic by one or two degrees because of the effect of building mass. Unless an extract is specifically designed to remove heat from hot spots or lights, the extract and room temperature can be taken to be the same. 

The maximum temperature which the desired reaction can reach under conditions of cooling failure can be determined from the adiabatic temperature rise, calculated from the remaining heat of reaction and the specific heat of the reactants. If this temperature is high enough to boil the reaction mass or to start a secondary or decomposition reaction under the plant conditions, a hazardous situation may occur. 

The size of the copper plane, 40 sq. in., is selected on the x-axis of Fig. 16.10. The distance from trace to the plane, 0.02 in., is the second curve from the top in Fig. 16.10. The coefficient is found on the y-axis directly across from the intersection of the curve and copper plane area. The trace temperature rise will be approximately 0.42 times the temperature rise calculated from Fig. 16.5 or Fig. 16.6. 

For the case of natural convection cooled TRIGA reactors, the reactor thermal power is calibrated by measuring pool water temperature rise. A PC can measure the temperature and power monitor values during the experiment, fit temperature rise, calculate thermal power, and give calibration value for each power monitor. 

Approximate temperature rise calculated from previous column"... 

The relatively large temperature rises calculated by the subchannel analyses and statistical thermal design shown that these analyses are essential in determining the maximum peak cladding temperature of the Super LWR core. 

Flash Evaporators The calculation of a heat and material balance on a flash evaporator is relatively easy once it is understood that the temperature rise in each heater and temperature drop in each flasher must all be substantially equal. The steam economy E, kg evap-oration/kg of I055-kJ steam (Ib/lb of lOOO-Btu steam) may be approximated from... 

What is the potential temperature rise by the desired reaction What is the rate of the temperature rise Enthalpy of desired reaction Specific heat Table of data Thermodynamic data Calculations estimations... 

Note If the manufacturer can ascertain that a 100 h.p. frame has a reserve capacity such that at full load the temperature rise will not go beyond 60°C, the derating as calculated below will not be necessary. 

In our sample calculations (Example 3 1.1) we have chosen the colour of the outdoors surface as light grey and taking the vveathering effect into account, have considered the coefficient of both absorption and emission as 0.65. The manufacturer, depending on the colour and site conditions, may choose a suitable coefficient. It is, however, advisable to be conservative when deciding the temperature rise due to solar radiation to be on the safe side. 

The Hvp, vapor head, is calculated by ob.serving the fluid temperature, and then consulting the water properties graph in this chapter. Let s say we re pumping water at 50° F (10° C). The Hvp is 0.411 feet. If the water is 212° F (100° C) then the Hvp is 35.35 feet. The vapor head is subtracted because it robs energy from the fluid in the suction pipe. Remember that as the temperature rises, more energy is being robbed from the fluid. Next, we mu.st subtract the Hf... 

Calculate approximate air temperature rise from where... 

The screw compressor can be evaluated using the adiabatic work equation. Discharge temperature can be calculated by taking the adiabatic temperature rise and dividing by the adiabatic efficiency then multiplying by the... 

The exit region of a die used to extrude a plastic section is 10 mm long and has the cross-sectional dimensions shown below. If the channel is being extruded at the rate of 3 m/min calculate the power absorbed in the die exit and the melt temperature rise in the die. Flow curves for the polymer melt are given in Fig. 5.3. The product pCp for the melt is 3.3 x 10. ... 

Calculating the temperature rise at each time t with Eq. (4.326) and Eq. (4.328) gives the corresponding change in humidity. As the function G and the pressure p(T, u) are complex, numerical solutions are used. 

An accurate indication is achieved by carrying out the calculations in small time steps, such as At = 0.004 s, and then by calculating the vaporization, humidity change, and corresponding temperature rise at each time step. This is the numerical solution of differential equations (4.326) and (4.328). The results of a calculation of this type are shown in Table 4.12. 

A solution of 61 parts 4-chloro-l,l-di-(4-fluorophenyl)-l-butene in 400 parts 2-propanol is hydrogenated at normal pressure and at room temperature in the presence of 5.5 parts palladium-on-charcoal catalyst 10% (exothermic reaction, temperature rises to about 30°C). After the calculated amount of hydrogen is taken up, hydrogenation is stopped. The catalyst is filered off and the filtrate is evaporated. The oily residue is distilled in vacuo, yielding l-chloro-4,4-di-(4-fluorophenyl)-butane, boiling point 166° to 168°C at 6 mm pressure ... 

Calculate water required with selected temperature rise. This rate should fall between 2-10 gpm per lin ft of... 

In transporting this water through insulated pipes to the process equipment, it is good practice to allow a 2°F temperature rise when planning heat transfer calculations. 

Determine discharge temperature, Tg, using adiabatic temperature rise Equation 12-62. Use k values for gas or mixture or calculate them by Equation 12-4. 

If the case had been cooled internally, then the isen-tropic k value can be used to calculate the temperature rise. 

The temperature rises given in the preceding table are based upon a reference ambient temperature of 40°C. Motors intended for use in higher ambient temperatures should have temperature rises not exceeding the value calculated from the appropriate formula, rounded off to the nearest 5 degrees. 

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