I need to design a gas burner for a helical coil heat exchanger, but I\'m strugg

Question

I need to design a gas burner for a helical coil heat exchanger, but I'm struggling with some stuff Firsty while designing a gas burner, should the BTU/hour be the same for the gas burner as for the heat exchanger? On the internet one can find the flame temperature for propane gas as 1925oC, but some gas burner are larger than others, and also obviously hotter, so how would you calculate the temperature of the burner? Now if I have a temperature for the burner I plan on using a fan to increase the flow rate of the hot products over the heat exchanger, how would one calculate the temperature of the products before it passes over the burner?

Explanation / Answer

1. Assuming you want to use the gas burner as heat source for the heating up one coil of the heat exchanger, there will be some heat loss to surroundings firstly between gas burner and coil and secondly due to the effectiveness of your heat exchanger.

You need to measure how much heat is obtained on the other side of the heat exchanger for a given amount of gas burnt. Using calorific valyeof gas obtain heat supplied and then calculate the efficiency with which heat moves from burner to heat exchanger.

2. Gas burners being larger implies that they can burn more gas per unit time than smaller burners. The flame temperature for a given gas remains constant for all burners working under similar conditions. Because the amount of vas burnt is more we obtain higher heat transfered per unit time. So all you need to know is the mass of gas burnt per unit time and the calorific value of the gas per unit mass and you'll have the heat supplied by gas burner.

3. The heat transfered from hot gases to heat exchanger will be due to convection. Heat transfer rate will depend on temperature difference at a given point, and area available for heat absorption. The temperature variation for constant area throughout the height of heat exchanger will vary exponentially. So you need to measure temperature difference at the bottom and at the top and for any intermediate point use exponential curve for the temperature difference.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.