gas filled tube has 2 mm inside diameter and 25 cm length. The gas is heated by an electrical wire of diameter 50 microns (o.05 mm) located along the axis of the tube. Current and voltage drop across the heating element are 0.5A and 4 volts, respectively. If the measured wire and inside tube wall temps are 175C and 150C respectively, find the thermal conductivity of the gas filling the tube

gas filled tube has 2 mm inside diameter and 25 cm length. The gas is heated by an electrical wire of diameter 50 microns (o.05 mm) located along the axis of the tube. Current and voltage drop across the heating element are 0.5A and 4 volts, respectively. If the measured wire and inside tube wall temps are 175C and 150C respectively, find the thermal conductivity of the gas filling the tube

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

See similar textbooks

Similar questions

The composite wall of an oven consists of three materials, two of which are ofknown thermal conductivity, kA = 25 W/m ⋅ K and kC = 60 W/m ⋅ K, and knownthickness, LA = 0.40 m and LC = 0.20 m. The third material, B, which is sandwichedbetween materials A and C, is of known thickness, LB = 0.20 m, but unknownthermal conductivity kB. Under steady-state operating conditions, measurementsreveal an outer surface temperature of Ts,o = 20°C, an inner surface temperature ofTs,i = 600°C, and an oven air temperature of T∞ = 800°C. The inside convection coefficient h is known to be 25 W/m2 ⋅K. Neglecting convection transfer effect,what is the value of kB?
Determine the resistance of an aluminium coil of 140 cm as diameter consists of 15800 turns and the mean length per turn is 4305 cm. Take the electrical conductivity of the aluminium coil as 0.24 MS/m. Solution: Area of Cross-section of the Coil (in m?) 1.53 Total Length (in m) 680190 The Resistance of the Coil (in 2) 1.849
4. Two aluminum blocks with different dimensions, but the same mass are shown in the figure. The dimensions of block 1 are 0.25 cm in thickness, 3 cm in width, and 36 cm in length. The dimensions of block 2 are 3 cm for each side of the cube. Aluminum has a density of 2700 kg/m³ and a specific heat capacity of 900 J/kg-°C. The value of the heat transfer coefficient to the surrounding air is 10 W/m²-°C. 0.25 cm 36 cm 3 cm 3 cm Block 1 3 cm Block 2 3 cm Complete the following. (a) Calculate thermal time constant (in min) for both blocks. (b) Each block is heated to an initial temperature 120 °C and then allowed to cool in the surrounding air which is at 20 °C. Write a script file in MATLAB® that plots the temperature as a function of time, T(t), for both blocks on the same graph. Plot the temperature of block 1 using a solid black line and the temperature of block 2 using a dotted black line. Plot for a duration equal to four of the longer time constant between blocks 1 and 2. The time…
The figure shows the cross section of a wall made of three layers. The thicknesses of the layers are L₁, L2=0.750 L₁, and L3 = 0.350 L₁. The thermal conductivities are k₁, k₂ = 0.840 k₁, and k3 = 0.780 k₁. The temperatures at the left and right sides of the wall are TH = 23 °C and Tc = -10 °C, respectively. Thermal conduction is steady. (a) What is the temperature difference AT2 across layer 2 (between the left and right sides of the layer)? If k2 were, instead, equal to 1.160 k₁, (b) would the rate at which energy is conducted through the wall be greater than, less than, or the same as previously, and (c) what would be the value of AT2? TH k₁ L₁ kg|kz kq L₂ L3 Tc
As shown in the sketh below, a steam pipe of 0.12-m inside diameter is insulated with a layer of calcium silicate. "2. Ta2} 1. Ta,1} Steam Insulation (a) If the insulation is 10 mm thick and its inner and outer surfaces are maintained at T, = 800 K and Ta = 490 K. respectively,. what is the rate of heat loss per unit length (q) of the pipe, in W/m? (b) Determine the rate of heat loss per unit length (d), in W/m, and outer surface temperature T,2, in K, for the steam pipe with the Inner surface temperature fixed at T = 800 K, inner radius = 0.06 m, and outer radius n = 0.18 m. The outer surface is exposed to an airflow (T 25°C) that maintains a convection coefficient of h = 25 W/m2-K and to large surroundings for which Tur = T, = 25°C. The surface emissivity of calcium silicate is approximately 0.8.
The wall of a furnace comprises three layers as shown in the figuie. The first layer is tery (whose maximum allowable temperature is 1400°C) while the second laver is Tracto:y Chose maximum allowable temperature is 1093°C). The third layer is a plate of 6 35 od thermal contact. Steet plare To 6.35x3 45A 1370 C Concerntiation veluciy 37.8 C mass Siynes Figure. Layers in a composite furnace wall. e temperature To on the inside of the refractory is 1370°C, while the temperature T; on the side of the steel plate is 37.8° The heat loss through the furnace HnIlisexpectet tobe
The rate of heat generation per unit volume in a plane wall of thickness 30 mm can be modeled as: q=1000-7000x? If the temperature of wall at x = 0 is 100 °C and at x = 30 mm is 70 °C, then find the mid-plane temperature. Take thermal conductivity of plane wall equal to 5W/m-K
Determine the resistance of an aluminium coil of 197 cm as diameter consists of 13100 turns and the mean length per turn is 3925 cm. Take the electrical conductivity of the aluminium coil as 0.38 MS/m. Solution: Area of Cross-section of the Coil (in m?) Total Length (in m) The Resistance of the Coil (in Q)
Find the thermal resistance r (in hr - °F/BTU) and the equivalent R-value (in hr ft?. °F/BTU) of a typical frame 20' x 7.5" wall consisting of a 0.5" plaster board on the inside of the room, nominai 2 x 4 studs, and a 0.5" sheathing on the outside. The spaces between the studs are filled with an R-15 insulating foam. What is the heat loss (in BTU) through this wall in four hours if the inside temperature is 72°F and the outside temperature is 32°F? (Assume that the 15% of the wall's area are studs and the remaining 85% is filled with the insulating foam. Assume that the air is moving outside the wall.) r= 0.0805 x hr: OF/BTU R=0.09 x hr ft2. F/BTU AQ = BTU
Determine the resistance of an aluminium coil of 183 cm as diameter consists of 14500 turns and the mean length per turn is 4883 cm. Take the electrical conductivity of the aluminium coil as 0.37 MS/m. Solution: Area of Cross-section of the Coil (in m²) Total Length (in m) The Resistance of the Coil (in 2) o search
Determine the resistance of an aluminium coil of 102 cm as diameter consists of 15900 turns and the mean length per turn is 3450 cm. Take the electrical conductivity of the aluminium coil as 0.2 MS/m. Solution: Area of Cross-section of the Coil (in m2) Total Length (in m) The Resistance of the Coil (in Q)