Mass flow measurement overall

Closure normally begins by satisfying the overall mass balance i.e., by equating the input and outlet mass flow rates for a steady-state system. For the present case, the outlet flow was measured. The inlet flow was unmeasured so it must be assumed to be equal to the outlet flow. We suppose that A and B are the only reactive components. Then, for a constant-density system, it must be that... 

Equation (2) states that, to obtain the magnitude of the overall steady-state conversion efficiency, the mass flows of conversion gas and solid fuel need to be measured, as well as the mineral contents of the solid fuel. 

The mass flow rates of air and fuel were measured with a set of float-type flow meters to a precision of 1%, and the overall equivalence ratio was determined with an uncertainty of less than 2%. The swirl number of the second-flow arrangement was defined at the exit of the swirler as... 

Ortiz, et. al (1999) measured overall mass transfer coefficients for the aqueous dissolution of naphthalene, pyrene, and phenanthrene from oils ranging in viscosities from a light lubricating oil (86 cp) to a high viscosity oil ( 1000cp). These measurements were performed in continuous-flow systems for time periods ranging from several months up to one year. The authors hypothesize that naphthalene, pyrene, and phenanthrene dissolution from a high viscosity oil (1000 cp) results in a depleted zone within the NAPL that increases with dissolution time. 

The typical pressure profile of the standpipe and the valve is shown in Fig. 8.18. As can be seen in the figure, the pressure head over the standpipe Aps, in the absolute sense, is equal to the sum of the overall pressure head, Apt, and the pressure drop over the valve, Ap0. From Eq. (8.92), the particle volume fraction in the standpipe can be estimated from the measured height of the bulk particles. Thus, given the particle mass flow rate, the leakage flow of gas in the standpipe can be estimated from Eq. (8.95). 

SOLUTION During an experiment involving an automotive radiator, the inlet and exit temperatures of water and air and the mass flow rate of water are measured. The overall heat transfer coefficient based on the inner surface area is to be determined. 

However, also this calorimetric principle is not without weaknesses. Equ.(4-226) shows that the exact knowledge of the coolant mass flow is pivotal to the overall accuracy of the measurement. Today s commercially available calorimeters are equipped with pumps for the coolant like those known in type from thermostats. They are not able to provide a frilly constant mass flow rate, especially not if the experiment lasts several hours. Furthermore, the preinstalled mass flow meters usually are rotameters of quite a simple type. 

To characterize the sensors, they were placed inside a measurement chamber, which was itself mounted in a temperature-controlled oven (Fig. 3). The atmosphere in the measurement chamber could be controlled via gas-mixing equipment involving mass-flow controllers. The chamber was first heated up to 270 °C in a nitrogen (Nj) atmosphere. When the steady state was reached, selected amounts of propane, propene and water were added to the nitrogen carrier gas. The overall gas-flow was held constant at 500 cmVmin. The analytes were prethinned to 800 ppm in nitrogen carrier gas. A bubbler was used for the humidification of the gas. 

The authors estimated an overall uncertainty of the mean isobaric specific heat capacity of less than 0.15%. Test measurements with water and w-pentane support this estimation. From the extrapolation of the mass flow rate dependence, they determined a maximum loss heat flow rate of 0.05% of the electric heating power, the latter being larger than 11W. 

In a fashion that has already been described in Chapter 1, Volume 2 of this series, the inlet and the ouflet moisture content of the air, Yj and Yo t. respectively, were measured by infrared spectroscopy, so that with known mass flow rate of dry gas. Mg, and hold-up of dry solids, M, the overall water balance was used to calculate... 

In this experiment, the gas flow is at first established for a specified mass flow rate and then the particles are fed into the pipeline. After transient period a steady state is reached in a sense that the particle mass flow rate and the average pressure reading become constant. Changing the gas velocity carries out the ejqjeriment and we measure the overall pressure drop after the obstruction, particle mass flow rate and jump position 1. 

It should be pointed out that Eq. (4.124) was derived without invoking fluctuations of contour length (i.e., without considering the Rouse motion in a reptating chain). The main idea behind the derivation of Eq. (4.124) is that since experimental data for r)Q is usually obtained from shear flow measurements, stress effects must be included in the reptation model that is, when a polymer is subjected to shear flow, a relaxation of polymer chains to reptate around the entangled junctions must be taken into consideration, in addition to the reptation of the overall center-of-mass motion. 

---