Burner

• US 5,588,826 A
• Filed: 08/03/1995
• Issued: 12/31/1996
• Est. Priority Date: 10/01/1994
• Status: Expired due to Term

• Current Assignee: Alstom Technology Ltd. (Alstom SA)
• Original Assignee: ABB Management AG (ABB Limited)
• Inventors: Sattelamayer, Thomas, Steinbach, Christian, Paikert, Bettina, Ruck, Thomas, Haumann, Jurgen, Dobbeling, Klaus, Knopfel, Hans P.
• Primary Examiner(s): Yeung, James C.
• Application Number:
  US08/510,659
• Time in Patent Office: 516 Days
• Field of Search: 431/2, 431/8, 431/9, 431/10, 431/183, 431/185, 431/351-354, 239/402
• US Class Current: 431/354
• CPC Class Codes: F23C 2202/40 Inducing local whirls around flame
• CPC Class Codes: F23C 2900/07002 Premix burners with air inlet slots obtained between offset curved wall surfaces, e.g. double cone burners
• CPC Class Codes: F23D 11/402 Mixing chambers downstream of the nozzle
• CPC Class Codes: F23D 17/002 gaseous or liquid fuel
• CPC Class Codes: F23D 2209/10 Flame flashback
• CPC Class Codes: F23D 2209/20 Flame lift-off / stability

Abstract

In a burner which consists of a swirl generator (100) on the oncoming-flow side, the flow (40) formed herein is passed smoothly into a mixing section (220). This is done with the aid of a transition geometry which is present at the start of the mixing tube (220) and consists of transition passages (201) which cover sectors of the end face of the mixing section (220), in accordance with the number of sectional bodies of the swirl generator (100), and run helically in the direction of flow. On the outflow side of these transition passages (201), prefilming bores (21) pass through the mixing section (220), which prefilming bores (21) initiate an increase in the flow velocity along the tube wall. Adjoining the mixing section (220) is a combustion chamber (30) in which a backflow zone (50) forms in the region of the jump in cross-section between mixing section (220) and combustion chamber (30).

Claims

1. A burner for a heat generator, the burner having a direction of flow, comprising:

a swirl generator for introducing a swirled combustion air flow into the burner;

means for injecting fuel into the combustion air flow in the swirl generator;

a mixing section connected at a downstream end of the swirl generator to receive the combustion air flow and fuel; and

transition means between the swirl generator and the mixing section including transition passages to guide the swirled combustion air flow and injected fuel from the swirl generator into the mixing section.

2. The burner as claimed in claim 1, wherein the mixing section is a tubular mixing element.

3. The burner as claimed in claim 1, wherein the swirl generator is formed of at least two sectional bodies defining an interior space, and the transition passages in the mixing section correspond in quantity to the sectional bodies forming the swirl generator.

4. The burner as claimed in claim 1, wherein a portion of the mixing section downstream of the transition passages includes openings along the direction of flow and about a periphery, the openings acting as prefilming bores for injecting an air flow into the mixing section.

5. The burner as claimed in claim 1, wherein a portion of the mixing section downstream of the transition passages includes tangential openings for an air flow into the mixing section.

6. The burner as claimed in claim 1, wherein a cross-section flow area of the mixing section downstream of the transition passages is less than a cross-section flow area in the swirl generator.

7. The burner as claimed in claim 1, wherein the transition passages open into an upstream end face of the mixing section and are oriented helically in the direction of flow.

8. The burner as claimed in claim 1, further comprising a diffuser disposed at a downstream end of the mixing section.

9. The burner as claimed in claim 1, further comprising a combustion chamber connected downstream of the mixing section, wherein an upstream end factor the combustion chamber defines a radially increasing jump in cross-section between the mixing section and the combustion chamber, which jump in cross-section defines an initial cross-section of flow of the combustion chamber, and defines a region in the combustion chamber wherein a backflow zone is formable.

10. The burner as claimed in claim 1, wherein the swirl generator comprises at least two hollow, conical sectional bodies nested one inside the other and aligned in the direction of flow to form a conical interior space, respective longitudinal symmetry axes of the sectional bodies being mutually offset so that adjacent walls of the sectional bodies form longitudinally extending ducts for a tangentialy directed combustion-air flow into the interior space, and wherein the means for injecting fuel comprises at least one fuel nozzle disposed for injecting fuel in the conical interior space.

11. The burner as claimed in claim 10, further comprising fuel nozzles arranged in a region of the longitudinally extending ducts in the longitudinal extent to inject fuel into the tangentially directed flow.

12. The burner as claimed in claim 10, wherein each of the sectional bodies has a blade-shaped profile in cross-section.

13. The burner as claimed in claim 10, wherein the sectional bodies have a fixed cone angle in the direction of flow.

14. The burner as claimed in claim 10, wherein the sectional bodies are nested spirally one inside the other.

15. The burner as claimed in claim 10, wherein the sectional bodies are shaped to have a cone angle that increases in the direction of flow.

16. The burner as claimed in claim 10, wherein the sectional bodies are shaped to have a cone angle that decreases in the direction of flow.

17. The burner as claimed in claim 1, wherein a cross-section flow area of the mixing section downstream of the transition passages is at least equal to a cross-section flow area in the swirl generator.

18. The burner as claimed in claim 1, wherein the transition passages are formed as recesses in a wall of the transition means which communicate with the swirl generator.