Since the correlation given in the textbook is so complicated, for convection over a sphere. proposes the correlation to be NUD = 2+ C Re Pr¹/3 used a steel sphere (conductivity of 42 W/m-K) of 20 cm diameter that generates steady 40 W heat. placed it in air flow with 1 m/s where air temperature is 20°C. then measured the steady state tempera- ture of the sphere surface to be 30°C. Based on come up with a new correlation 2 measurements, what is the convection coefficient? 318 W/m²K Using properties at film temperature, what should the value of C be as per assumes m = 0.8? 0.142 What is the temperature at the center of the sphere? 30'38 ℃ calculations if

Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
icon
Related questions
Question

onyl attempt once

**Correlation for Convection Over a Sphere**

Since the correlation given in the textbook is so complicated, a new correlation is proposed for convection over a sphere:

\[ \overline{NU_D} = 2 + C \, \text{Re}_D^m \, \text{Pr}^{1/3} \]

A steel sphere with a conductivity of 42 W/m·K and a diameter of 20 cm generates a steady 40 W of heat. It is placed in an airflow with a speed of 1 m/s where the air temperature is 20°C. The steady-state temperature of the sphere surface is then measured to be 30°C.

1. **Based on these measurements, what is the convection coefficient?**  
   **31.8 W/m²·K**

2. **Using properties at film temperature, what should the value of C be as per calculations if m = 0.8?**  
   **0.142**

3. **What is the temperature at the center of the sphere?**  
   **30.38°C**
Transcribed Image Text:**Correlation for Convection Over a Sphere** Since the correlation given in the textbook is so complicated, a new correlation is proposed for convection over a sphere: \[ \overline{NU_D} = 2 + C \, \text{Re}_D^m \, \text{Pr}^{1/3} \] A steel sphere with a conductivity of 42 W/m·K and a diameter of 20 cm generates a steady 40 W of heat. It is placed in an airflow with a speed of 1 m/s where the air temperature is 20°C. The steady-state temperature of the sphere surface is then measured to be 30°C. 1. **Based on these measurements, what is the convection coefficient?** **31.8 W/m²·K** 2. **Using properties at film temperature, what should the value of C be as per calculations if m = 0.8?** **0.142** 3. **What is the temperature at the center of the sphere?** **30.38°C**
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps

Blurred answer
Knowledge Booster
Convection
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Elements Of Electromagnetics
Elements Of Electromagnetics
Mechanical Engineering
ISBN:
9780190698614
Author:
Sadiku, Matthew N. O.
Publisher:
Oxford University Press
Mechanics of Materials (10th Edition)
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:
9780134319650
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Thermodynamics: An Engineering Approach
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:
9781259822674
Author:
Yunus A. Cengel Dr., Michael A. Boles
Publisher:
McGraw-Hill Education
Control Systems Engineering
Control Systems Engineering
Mechanical Engineering
ISBN:
9781118170519
Author:
Norman S. Nise
Publisher:
WILEY
Mechanics of Materials (MindTap Course List)
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:
9781337093347
Author:
Barry J. Goodno, James M. Gere
Publisher:
Cengage Learning
Engineering Mechanics: Statics
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:
9781118807330
Author:
James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:
WILEY