Heat transfer and pressure drop in a reciprocating blind duct with swirls generated by a lateral entry jet

Shyy-Woei Chang, Zong Xian Cai

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This experimental study simulates the advanced piston cooling passage of a marine propulsive diesel engine to examine the heat transfer performance of a reciprocating square blind duct with swirl induced by injecting a lateral jet. The detailed Nusselt number (Nu) distributions over two opposite walls, namely the jet wall and the back wall, of the reciprocating blind duct at channel (jet) Reynolds numbers Re(Re j ) of 1500 (6000), 2000 (8000), 3000 (12,000), 5000 (20,000), 7000 (28,000) and 10,000 (40,000) with reciprocating frequencies of 0, 0.67, 0.83, 1 and 1.17Hz are measured using the steady-state infrared thermo-graphic method. The jet flows and the jet-induced swirl, which improve heat transfer performance considerably, interact with the reciprocating and buoyancy forces to exhibit synergistic impacts on Nu distributions. This is demonstrated by comparatively examining a set of full-field Nu distributions to illustrate the Nu variations responding to the changes of Re j , pulsating (Pu) and reciprocating Grashof (Gr p ) numbers. The individual and interdependent channel Reynolds number (Re), Pu and Gr p effects on the area-averaged Nusselt number (Nu-) are parametrically analyzed to devise Nu- correlations. A comparison with reported Nu- data for the various reciprocating channels indicates the favorable heat transfer performance for the present jet-swirl system. Due to the combined Re, Pu and Gr p effects, the Nu- over the jet wall and back wall are respectively raised to 0.78-1.3 and 0.8-1.51 times of the static heat transfer levels. Nevertheless, the high pressure potentials required to facilitate the lateral jet and to overcome the viscous frictions and the pressure drop through the enlargement of flow passage are observed, leading to significant increases of the pressure drop coefficient (f) from the static smooth pipe flow reference (f ). The thermal performance factors (η) defined on the basis of constant pumping power consumption for such flow configuration relative to the smooth pipe flow condition and the static jet-swirl condition are evaluated.

Original languageEnglish
Pages (from-to)1067-1085
Number of pages19
JournalExperimental Thermal and Fluid Science
Volume35
Issue number6
DOIs
Publication statusPublished - 2011 Sep 1

Fingerprint

Ducts
Pressure drop
Heat transfer
Pipe flow
Nusselt number
Reynolds number
Graphic methods
Buoyancy
Pistons
Diesel engines
Electric power utilization
Friction
Cooling
Infrared radiation
O-beta-ribosyl(1''-2')-guanosine-5''-phosphate

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Nuclear Energy and Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

Cite this

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title = "Heat transfer and pressure drop in a reciprocating blind duct with swirls generated by a lateral entry jet",
abstract = "This experimental study simulates the advanced piston cooling passage of a marine propulsive diesel engine to examine the heat transfer performance of a reciprocating square blind duct with swirl induced by injecting a lateral jet. The detailed Nusselt number (Nu) distributions over two opposite walls, namely the jet wall and the back wall, of the reciprocating blind duct at channel (jet) Reynolds numbers Re(Re j ) of 1500 (6000), 2000 (8000), 3000 (12,000), 5000 (20,000), 7000 (28,000) and 10,000 (40,000) with reciprocating frequencies of 0, 0.67, 0.83, 1 and 1.17Hz are measured using the steady-state infrared thermo-graphic method. The jet flows and the jet-induced swirl, which improve heat transfer performance considerably, interact with the reciprocating and buoyancy forces to exhibit synergistic impacts on Nu distributions. This is demonstrated by comparatively examining a set of full-field Nu distributions to illustrate the Nu variations responding to the changes of Re j , pulsating (Pu) and reciprocating Grashof (Gr p ) numbers. The individual and interdependent channel Reynolds number (Re), Pu and Gr p effects on the area-averaged Nusselt number (Nu-) are parametrically analyzed to devise Nu- correlations. A comparison with reported Nu- data for the various reciprocating channels indicates the favorable heat transfer performance for the present jet-swirl system. Due to the combined Re, Pu and Gr p effects, the Nu- over the jet wall and back wall are respectively raised to 0.78-1.3 and 0.8-1.51 times of the static heat transfer levels. Nevertheless, the high pressure potentials required to facilitate the lateral jet and to overcome the viscous frictions and the pressure drop through the enlargement of flow passage are observed, leading to significant increases of the pressure drop coefficient (f) from the static smooth pipe flow reference (f ∞ ). The thermal performance factors (η) defined on the basis of constant pumping power consumption for such flow configuration relative to the smooth pipe flow condition and the static jet-swirl condition are evaluated.",
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Heat transfer and pressure drop in a reciprocating blind duct with swirls generated by a lateral entry jet. / Chang, Shyy-Woei; Cai, Zong Xian.

In: Experimental Thermal and Fluid Science, Vol. 35, No. 6, 01.09.2011, p. 1067-1085.

Research output: Contribution to journalArticle

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N2 - This experimental study simulates the advanced piston cooling passage of a marine propulsive diesel engine to examine the heat transfer performance of a reciprocating square blind duct with swirl induced by injecting a lateral jet. The detailed Nusselt number (Nu) distributions over two opposite walls, namely the jet wall and the back wall, of the reciprocating blind duct at channel (jet) Reynolds numbers Re(Re j ) of 1500 (6000), 2000 (8000), 3000 (12,000), 5000 (20,000), 7000 (28,000) and 10,000 (40,000) with reciprocating frequencies of 0, 0.67, 0.83, 1 and 1.17Hz are measured using the steady-state infrared thermo-graphic method. The jet flows and the jet-induced swirl, which improve heat transfer performance considerably, interact with the reciprocating and buoyancy forces to exhibit synergistic impacts on Nu distributions. This is demonstrated by comparatively examining a set of full-field Nu distributions to illustrate the Nu variations responding to the changes of Re j , pulsating (Pu) and reciprocating Grashof (Gr p ) numbers. The individual and interdependent channel Reynolds number (Re), Pu and Gr p effects on the area-averaged Nusselt number (Nu-) are parametrically analyzed to devise Nu- correlations. A comparison with reported Nu- data for the various reciprocating channels indicates the favorable heat transfer performance for the present jet-swirl system. Due to the combined Re, Pu and Gr p effects, the Nu- over the jet wall and back wall are respectively raised to 0.78-1.3 and 0.8-1.51 times of the static heat transfer levels. Nevertheless, the high pressure potentials required to facilitate the lateral jet and to overcome the viscous frictions and the pressure drop through the enlargement of flow passage are observed, leading to significant increases of the pressure drop coefficient (f) from the static smooth pipe flow reference (f ∞ ). The thermal performance factors (η) defined on the basis of constant pumping power consumption for such flow configuration relative to the smooth pipe flow condition and the static jet-swirl condition are evaluated.

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