###### Industrial Heating Principles, Techniques, Materials, Applications, and Design

67 SOLVED PROBLEMS

Question: 9.1

## A resistance-heated furnace is to be designed with following requirements: Working space = 30 × 40 × 100 cm Occasional maximum temperature = 1250°C Continuous working temperature = 1150°C Atmosphere = Air Estimated power = 24 kW Available voltage = 440 V–3ph Specific resistivity ...

The furnace atmosphere is oxidizing. Working tempe...
Question: 9.3

## Design an indirect resistance furnace as specified below. Working Space 60 × 45 × 90 cm Continuous temperature 1550°C Occasional maximum temperature 1600°C Estimated power 52 kW Electric supply 380 V, 3 ph Now determine: Heater material No. of heaters and connections Voltage and current Transformer ...

Working volume = 45 (W) × 60 (H) × 90 (D) 2.5 × [l...
Question: 5.1

## A fuel oil has following properties: Analysis W +% Carbon – 86.20 Hydrogen – 12.30 Sulfur – 1.50 Calorific value – 43.40 MJ/kg Theoretical air for combustion – 10.71 m³/kg oil Volume of combustion products – 11.40 m³/kg Composition of combustion products, % volume CO2 – 13.5% H2O – 12.3% N2 – 74.2% ...

The combustion reaction for oil can be written as ...
Question: 10.1

## Determine the depth of penetration for 0.4% carbon steel heated from 30–900°C at 1000 Hz. The resistivity and permeability at various temperatures is given below. ...

\delta=5030 \sqrt{\frac{\rho}{\mu_\gamma f}...
Question: 9.4

## Design a heating element for heating a metal specimen in a hot stage microscope. Specimen size 25 mm diameter 15 mm thick Maximum temperature 1500°C Atmosphere Air or Helium/Argon Power estimate for hot chamber 800 W ...

The heating element required has to be very compac...
Question: 9.2

## A muffle furnace is to be designed for silicon carbide heaters. Size of heating space (nominal) 28 (W) × 22 (H) × 120 (D) cm Maximum temperature 1400°C Atmosphere Air Estimated power 15 kW Power supply 380 V, 3 phase Heating elements to be situated at the top across the width. Now determine: ...

The width of the chamber is 28 cm. The heating ele...
Question: 4.7

## A two-layer furnace wall consists of a 60-mm ceramic wool material on the hot side and an 80-mm rock wool layer on the cold (outer) side. The initial temperature of the furnace and the atmosphere is 30°C. The heat is then turned on to obtain a temperature of 1250°C on the inside. Find the heat ...

For ceramic wool Thermal diffusivity \alpha...
Question: 5.4

## A fuel oil has the following composition (%) Carbon – 86.5 Hydrogen – 11.5 Oxygen – 1.0 N, S and ash – 1.0 Now determine: 1. The heating (calorific) value per kg 2. Air required for combustion 3. Volume and composition of combustion products 4. Theoretical combustion temperature 5. Composition and ...

Calorific value as per Mendeleev formula Q^...
Question: 5.3