WO1998019107A1 - Tube vaporigene - Google Patents

Tube vaporigene Download PDF

Info

Publication number
WO1998019107A1
WO1998019107A1 PCT/DE1997/002369 DE9702369W WO9819107A1 WO 1998019107 A1 WO1998019107 A1 WO 1998019107A1 DE 9702369 W DE9702369 W DE 9702369W WO 9819107 A1 WO9819107 A1 WO 9819107A1
Authority
WO
WIPO (PCT)
Prior art keywords
steam generator
tube
pipe
generator tube
tubes
Prior art date
Application number
PCT/DE1997/002369
Other languages
German (de)
English (en)
Inventor
Wolfgang Kastner
Wolfgang Köhler
Eberhard Wittchow
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO1998019107A1 publication Critical patent/WO1998019107A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10—Water tubes; Accessories therefor
    • F22B37/101—Tubes having fins or ribs
    • F22B37/103—Internally ribbed tubes

Definitions

  • the invention relates to a steam generator tube with ribs forming a thread on its inside. It also relates to a once-through steam generator with a gas flue, which is formed from vertically arranged steam generator pipes welded together in a gas-tight manner.
  • steam generator tubes which are welded together in a gas-tight manner via webs are usually used to form a gas flue, which are connected in parallel for the flow of a flow medium.
  • tubes that are already equipped with fins can also be used.
  • the steam generator tubes can be arranged vertically.
  • the steam generator tubes are generally designed in such a way that sufficient cooling of the steam generator tubes is ensured even at low mass flow densities of the medium flowing through the steam generator tubes.
  • a design criterion is the heat transfer behavior of a steam generator pipe.
  • a high heat transfer enables a particularly effective heating of the medium flowing through the steam generator tube with reliable cooling of the steam generator tube itself.
  • steam generator tubes are usually used which have a surface structure on their inside for generating a high heat transfer from their inner wall to the flow medium. From the European patent specification 0 503 116 AI a continuous steam generator with vertically arranged steam generator tubes is known. The steam generator tubes of this steam generator have an internal rib as a surface structure.
  • the invention is therefore based on the object of specifying a steam generator tube with ribs forming a thread on its inside, which also shows a particularly favorable heat transfer behavior when film boiling occurs.
  • a continuous steam generator is to be specified with a gas train formed from vertically arranged steam generator tubes which are welded together gas-tightly over fins and which can be operated particularly safely and reliably even in a pressure range of approximately 200 bar to 221 bar.
  • this object is achieved according to the invention in that its friction pressure loss determined at a Reynolds number of 400,000 without heating and with water as the flow medium is at least a factor of f> 0.9 • (1 + 2.15 • h) • d "0.152 than the friction pressure loss determined under the same conditions Smooth pipe with the same pipe length and with a pipe inside diameter equal to the equivalent pipe inside diameter d.
  • the equivalent inner tube diameter d of the steam generator tube which is given in meters, is defined as the inner tube diameter that a smooth tube with the same flow cross-section has.
  • the relative fin height h of the steam generator tube is defined as the ratio of fin height H and equivalent tube inner diameter d.
  • the invention is based on the knowledge that the heat transfer behavior of an internally finned steam generator tube in the state of film boiling is correlated with the friction pressure loss of the steam generator tube determined under the conditions mentioned. Surprisingly, as has been shown after extensive tests, a heat transfer coefficient that quantitatively describes the heat transfer behavior of the steam generator tube during film boiling is almost proportional to the loss of frictional pressure of the steam generator tube. Therefore, a steam generator tube with a suitably increased friction pressure loss has a correspondingly improved heat transfer behavior during film boiling.
  • the heat transfer behavior during film boiling can be improved by a suitable increase in the frictional pressure loss of the steam generator tube.
  • a particularly suitable improvement in its heat transfer behavior during film boiling which is particularly suitable for a safe and reliable mode of operation of the steam generator tube, results from the increase in its frictional pressure loss compared to a comparable smooth tube by at least the factor mentioned.
  • a steam generator tube designed according to the design concept mentioned also exhibits particularly good heat transfer behavior in the case of film boiling. This ensures particularly effective cooling of the steam generator tube by the medium flowing through, even during film boiling.
  • a continuous steam generator with steam generator tubes designed in this way can thus be operated particularly safely and reliably - even in a pressure range from approximately 200 bar to approximately 221 bar.
  • FIG. 1 shows a once-through steam generator in a simplified representation with the combustion chamber wall in vertical contact
  • FIG. 2 shows in longitudinal section a section of a steam generator tube used for piping the combustion chamber wall of the once-through steam generator
  • FIG. 3 shows the steam generator tube according to FIG. 2 in cross section and FIG , B, C and D.
  • a continuous steam generator 2 is shown schematically with a rectangular cross section, the vertical throttle cable is formed by a surrounding or combustion chamber wall 4 which merges into a funnel-shaped base 6 at the lower end.
  • a number of burners for a fuel are installed in an opening 8, only two of which are visible, in the combustion chamber wall 4 composed of steam generator tubes 10.
  • the vertically arranged steam generator tubes 10 are welded together gas-tight in the firing area V to form an evaporator heating surface 12.
  • the flue gas RG serves as a heating medium for the flow medium flowing in the steam generator tubes 10. Water or a water-steam mixture is provided as the flow medium in the exemplary embodiment.
  • each steam generator tube 10 has on its inside as a surface structure for generating a high heat transfer from the inner wall to the flow medium on a number of multi-threaded fins 30.
  • the ribs 30 forming the thread are due to their
  • the steam generator tubes 10 are designed, in particular with regard to the design of their internal fins, in such a way that their friction pressure loss at a Reynolds number of 400,000 without heating and with water as the flow medium is at least by the factor f> 0.9 • (1 + 2.15 • h ) • ⁇ r 0 ' 152 is greater than that of a comparable smooth tube under the same conditions.
  • d is to be understood as the equivalent inner tube diameter of the steam generator tube 10 measured in meters. This is defined as the inner pipe diameter that a smooth pipe with the same flow cross-section would have.
  • the relative fin height h is defined as the ratio of the actual fin height H and the equivalent pipe inside diameter d.
  • a comparable smooth pipe is also considered to be a smooth pipe with the same pipe length as the steam generator pipe 10 and with a pipe inside diameter equal to the equivalent pipe inside diameter d.
  • the design criterion for the steam generator tubes 10 is to be explained in more detail by means of the curves A, B, C, D shown in FIG. 4 in a coordinate system.
  • the increase factor f of the steam generator tube 10 which is defined by the ratio of the experimentally determined loss of friction pressure of the steam generator tube 10 to the experimentally determined friction pressure loss of a comparable smooth tube, is shown as a function of the equivalent inner tube diameter d.
  • the design criterion is that a steam generator tube with a relative fin height h of 0.03 should lie on or above curve A. Accordingly, a steam generator tube with a relative fin height h of 0.04, 0.05 or 0.06 should lie on or above the curve B, C or D.
  • each steam generator tube 10 has an equivalent inner tube diameter d of 25 mm and a relative fin height of 4%. Accordingly, each steam generator tube 10 is characterized in terms of its experimentally determined loss of friction pressure by an increase factor f of at least 1.71. In comparison, a commercially available steam generator tube has an increase factor of only 1.49. With the same mass throughput, the frictional pressure loss and therefore also the heat transfer coefficient during film boiling of the steam generator tube 10 are thus approximately 15% higher than in the known tube. In order to ensure equally safe and reliable cooling in comparison to the steam generator tube 10, the mass throughput in the known tube would therefore have to be increased by approximately 15%.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

Un tube vaporigène (10), lequel présente, même lors d'une ébullition pelliculaire, un coefficient de transmission thermique élevé et peut ainsi être refroidi de manière particulièrement fiable, présente selon l'invention une perte de pression par frottement déterminée pour un nombre de Reynolds de 400 000 sans chauffage et avec de l'eau comme milieu d'écoulement. Cette perte de pression par frottement est supérieure, par rapport à celle d'un tube lisse comparable déterminée dans des conditions identiques, d'au moins le facteur d'augmentation f≥0,9. (1+2,15. h) . d-0,152, lequel est fonction de la hauteur relative des nervures (h) et du diamètre intérieur de référence du tube (d) indiqué en mètres. Un générateur de vapeur continue (2) équipé d'un tel tube vaporigène (10) permet un fonctionnement particulièrement sûr et fiable même dans une plage de pression supérieure à environ 200 bars et jusqu'à environ 221 bars.
PCT/DE1997/002369 1996-10-28 1997-10-15 Tube vaporigene WO1998019107A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1996144763 DE19644763A1 (de) 1996-10-28 1996-10-28 Dampferzeugerrohr
DE19644763.1 1996-10-28

Publications (1)

Publication Number Publication Date
WO1998019107A1 true WO1998019107A1 (fr) 1998-05-07

Family

ID=7810216

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1997/002369 WO1998019107A1 (fr) 1996-10-28 1997-10-15 Tube vaporigene

Country Status (2)

Country Link
DE (1) DE19644763A1 (fr)
WO (1) WO1998019107A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009024587A1 (de) * 2009-06-10 2010-12-16 Siemens Aktiengesellschaft Durchlaufverdampfer
CN105806127B (zh) * 2016-05-03 2018-06-26 西安交通大学 一种具有流线型截面内肋的锅炉水冷壁内螺纹管

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0503116A1 (fr) 1991-03-13 1992-09-16 Siemens Aktiengesellschaft Tube avec plusieurs nervures hélicoidales sur sa paroi interne et générateur de vapeur en faisant usage
WO1992018807A1 (fr) * 1991-04-18 1992-10-29 Siemens Aktiengesellschaft Generateur de vapeur en continu avec cheminee a gaz constituee de conduits assembles pratiquement verticalement
DE4333404A1 (de) * 1993-09-30 1995-04-06 Siemens Ag Durchlaufdampferzeuger mit vertikal angeordneten Verdampferrohren

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4227457A1 (de) * 1992-08-19 1994-02-24 Siemens Ag Dampferzeuger
US5390631A (en) * 1994-05-25 1995-02-21 The Babcock & Wilcox Company Use of single-lead and multi-lead ribbed tubing for sliding pressure once-through boilers
DE4427859A1 (de) * 1994-08-05 1995-10-26 Siemens Ag Rohr mit auf seiner Innenseite ein mehrgängiges Gewinde bildenden Rippen sowie Dampferzeuger zu seiner Verwendung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0503116A1 (fr) 1991-03-13 1992-09-16 Siemens Aktiengesellschaft Tube avec plusieurs nervures hélicoidales sur sa paroi interne et générateur de vapeur en faisant usage
WO1992018807A1 (fr) * 1991-04-18 1992-10-29 Siemens Aktiengesellschaft Generateur de vapeur en continu avec cheminee a gaz constituee de conduits assembles pratiquement verticalement
DE4333404A1 (de) * 1993-09-30 1995-04-06 Siemens Ag Durchlaufdampferzeuger mit vertikal angeordneten Verdampferrohren

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
FRANKE J ET AL: "VERDAMPFERKONZEPTE FUR BENSON-DAMPFERZEUGER. HEUTIGER STAND UND NEUE ENTWICKLUNGEN", VGB KRAFTWERKSTECHNIK, vol. 73, no. 4, April 1993 (1993-04-01), pages 352 - 361, XP000647159 *

Also Published As

Publication number Publication date
DE19644763A1 (de) 1998-04-30

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