A model sphere with diameter d, soaked with ethanol, is kept still in a stream of...
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
A model sphere with diameter d, soaked with ethanol, is kept still in a stream of air. Dimensional analysis shows that the expression which relates the mass transfer coefficient of the ethanol evaporation, k, to the sphere diameter d, the mean air velocity, u, the diffusion coefficient of the ethanol in the air, D, and the air properties, density p and viscosity μ, is of the form: Sh = f(Re, Sc) where Sh = and Sc= μ pD kd D dup μ is the Sherwood number, Re = - is the Schmidt number. is the Reynolds number a) What is the significance of each of the dimensionless groups? A sphere, 5 cm in diameter, soaked in ethanol, is within a stream of air. Experiments have given the values reported in Table Q1 of the mass transfer coefficient of the ethanol in the air: Table Air velocity and mass transfer coefficient for the 5 cm sphere 30 40 10.8 13.4 air velocity (m s-¹) mass transfer coefficient (m s-¹) 10 4.5 20 7.6 b) Show for what range of air velocities can the above results be used for a sphere of 2 cm in diameter in the same air stream. c) What would be the mass transfer coefficients in the case of the 2 cm sphere? Air properties: density = 1.21 kg m-³, viscosity = 1.78 x 10-5 kg m-1 s-1. Diffusion coefficient of ethanol in air = 1.26 x 10-5 m² s-1. A model sphere with diameter d, soaked with ethanol, is kept still in a stream of air. Dimensional analysis shows that the expression which relates the mass transfer coefficient of the ethanol evaporation, k, to the sphere diameter d, the mean air velocity, u, the diffusion coefficient of the ethanol in the air, D, and the air properties, density p and viscosity μ, is of the form: Sh = f(Re, Sc) where Sh = and Sc= μ pD kd D dup μ is the Sherwood number, Re = - is the Schmidt number. is the Reynolds number a) What is the significance of each of the dimensionless groups? A sphere, 5 cm in diameter, soaked in ethanol, is within a stream of air. Experiments have given the values reported in Table Q1 of the mass transfer coefficient of the ethanol in the air: Table Air velocity and mass transfer coefficient for the 5 cm sphere 30 40 10.8 13.4 air velocity (m s-¹) mass transfer coefficient (m s-¹) 10 4.5 20 7.6 b) Show for what range of air velocities can the above results be used for a sphere of 2 cm in diameter in the same air stream. c) What would be the mass transfer coefficients in the case of the 2 cm sphere? Air properties: density = 1.21 kg m-³, viscosity = 1.78 x 10-5 kg m-1 s-1. Diffusion coefficient of ethanol in air = 1.26 x 10-5 m² s-1.
Expert Answer:
Answer rating: 100% (QA)
a The ratio of diffusive mass transfer to convective mass transfer is represented by the dimensionless group known as the Sherwood Number Sh This is t... View the full answer
Related Book For
Fundamentals of Heat and Mass Transfer
ISBN: 978-0471457282
6th Edition
Authors: Incropera, Dewitt, Bergman, Lavine
Posted Date:
Students also viewed these chemical engineering questions
-
As noted in Prob. 1.3, drag is more accurately represented as depending on the square of velocity. A more fundamental representation of the drag force, which assumes turbulent conditions (i.e., a...
-
Particles may aggregate in water as a result of their hydrophobicity or Van der Waals attractions. Such aggregates are called flocs and the process is termed flocculation. (Aerosols also can...
-
In the accompanying Sales Transactions data, use Excel's filtering capability to extract a. all orders that used Paypal. b. all orders under $100. c. all orders that were over $100 and used a credit...
-
Luper Company acquired a tract of land which contained iron deposits for $2,500,000. Luper spent $120,000 to access the iron ore. Luper estimates that 2,000,000 tons of ore will be extracted. The...
-
The Cash account in the general ledger of Lyco Corporation showed a balance of $21,749 at December 31 (but prior to performing a bank reconciliation). The companys bank statement showed a balance of...
-
Find the binary pair diffusivity for the system methane (A)-ethane (B) at \(293 \mathrm{~K}\) and \(1 \mathrm{~atm}\) by using the Lennard-Jones method given by Eq. (1.53) by the following methods....
-
Eighty units of end item E are needed at the beginning of week 6. Three cases ( 30 units per case) of J have been ordered and one case is scheduled to arrive in week 3, one in week 4, and one in week...
-
Consider a rm that only has a patent as its assets If not developed any further, the value of the patent will only be $19 million at the end of the year. The rm has long-term debt of $28 million,...
-
Mary Church, an internal accountant for Wardak Construction Consulting, is investigating a loss of $100,000 via four checks for $25,000 each. It appears that the checks had been stolen from the...
-
Write a paper about Gun ownership in schools
-
Derive the following Maxwell relations for open systems. a. Starting from Eq. 6.2-5a, b. Starting from Eq. 6.2-6a, c. Starting from Eq. 6.2-7a, d. Starting from Eq. 6.2-8a, (). HT ON (0) aN S, N S,V...
-
Write, compile, and simulate a Verilog description for the state machine diagram in Figure 6-38. Use code 00 for state STA, 01 for state STB, and 10 for state STC. Use a simulation input that passes...
-
Partial manufacturing cost data for Morton Company are presented below. Compute the missing amounts. Direct materials used Direct labor Manufacturing overhead Total manufacturing costs...
-
Write a VHDL description for the circuit specified in Problem 4-15. Problem 4-15: The state diagram for a sequential circuit appears in Figure 4-51. Figure 4-51: Input X Output Z Reset 1 A 0 0 0 0 E...
-
A sequential circuit with two D lip- lops A and B, one input Y, and one output Z is specified by the following input equations: (a) Draw the logic diagram of the circuit. (b) Derive the state table....
-
Suppose that you want to sequence the following two DNA fragments: (1) 5'-GCGCAATTCTTC-primer site-3' (2) 3'-primer site -AACCGGTACTAC-5' In each case you first use PCR to amplify the fragment, so...
-
On January 2, 20X3, Sheldon Bass, a professional engineer, moved from Calgary to Edmonton to commence employment with Acco Ltd., a large public corporation. Because of his new employment contract,...
-
A shell-and-tube heat exchanger with one shell pass and 20 tube passes uses hot water on the tube side to heat oil on the shell side. The single copper tube has inner and outer diameters of 20 and 24...
-
For laminar free convection from a heated vertical surface, the local convection coefficient may be expressed as hx = Cx-1/4, where h, is the coefficient at a distance x from the leading edge of the...
-
A row of regularly spaced cylindrical heating elements is used to maintain an insulated furnace wall at 500 K. The opposite wall is at a uniform temperature of 300 K. The insulated wall experiences...
-
Calculate the radius \(R_{S}\) of the orbit of a geostationary satellite using the lunar period, \(T=27.3\) d, and the Earth-Moon distance, \(D_{T L}=3.810^{5} \mathrm{~km}\), as data.
-
Show that in the case of a binary system in which the orbit is circular of radius \(r\), the kinetic energy corresponds to half the absolute value of the potential energy. In other words, the total...
-
Show that the force field expressed in spherical coordinates \(\mathbf{F}=f(r, \theta) \mathbf{r}\) is conservative if and only if the function \(f\) is independent of \(\theta\).
Study smarter with the SolutionInn App