The Graetz number is associated with___________________
Show answer Hide answer
Answer: D. Heat transfer in laminar flow
Explanation
The Graetz number is a dimensionless group that characterizes laminar heat transfer in internal pipe and conduit flows. It is defined mathematically as the mass flow rate multiplied by specific heat capacity divided by thermal conductivity and length. Low Graetz numbers indicate fully thermally developed flow, whereas high values signify developing thermal boundary layers. Dimensionless numbers help chemical engineers scale fluid flow and thermal transport data across different geometric scales. Laminar flow regimes occur at low Reynolds numbers where fluid particles move along smooth, orderly parallel streamlines. Thermal entrance regions require special dimensionless parameters because temperature profiles change continuously along the tube length.
Mass transfer between gas and liquid phases is typically characterized by Sherwood and Schmidt numbers rather than Graetz. Absorption with chemical reaction involves parameters like the Hatta number and enhancement factors instead. Heat transfer in turbulent flow is governed by Reynolds, Prandtl, and Nusselt numbers rather than laminar specific groups.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. What is the nutrient composition implied by a -10-5 fertilizer rating______________?
Show answer Hide answer
Answer: A. 5, 10, 5% respectively of N2, P2O5 and K2O
Fertilizer grades conventionally indicate the percentage composition of nitrogen, phosphate, and potash respectively. A standard numeric rating provides guaranteed analysis percentages for these three primary plant nutri...
Q2. How does the required number of stages respond when the reflux ratio in a continuous counter-current extraction setup is elevated_______________________?
Show answer Hide answer
Answer: B. Decrease
Increasing the reflux ratio returns more solvent back into the extraction column. This higher internal liquid traffic enriches the counter-current streams and improves separation efficiency. Consequently, fewer equilibri...
Q3. What is the reaction order depicted in the accompanying graphic, characterized by the rate expression -rA = KCA_________________?
Show answer Hide answer
Answer: D. 3
The rate expression convention and matching graphic coefficients determine reaction kinetics order. Complex chemical kinetics models evaluate the overall exponent sum in rate laws. Based on the provided rate expression p...
Q4. As ambient temperature climbs, the atomic heat capacities corresponding to all solid elemental substances_________________?
Show answer Hide answer
Answer: A. Increases
According to the Dulong-Petit law and general thermodynamic behavior, atomic heat capacities increase at high temperatures. Thermal agitation allows lattice atoms to vibrate with greater amplitudes, absorbing more therma...
Q5. How does the internal energy of a substance respond to an increase in temperature___________________?
Show answer Hide answer
Answer: A. Increases
Internal energy represents the total microscopic kinetic and potential energy stored within a given substance. Raising the temperature increases the average translational and rotational kinetic energy of its constituent...
Q6. What is the amount of work performed during the free expansion of a gas____________________?
Show answer Hide answer
Answer: B. Zero
Free expansion involves a gas rushing into an evacuated chamber against zero opposing external pressure. Mechanical work done is defined as the product of external pressure and the resulting volume change. Since external...