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Noise Reduction in Refrigerator Machine Room through MRV-based Structural Modifications
(Visualization of flow and pressure fields in the suction muffler of a reciprocating compressor using MRV)
The Multiscale Heat & Fluid Flow Lab (MFL) applies MRV-based techniques to characterize three-dimensional flow and turbulence structures in refrigerator machine rooms, with the goal of reducing flow-induced noise and enhancing energy efficiency. A 1/2 scale model of the machine room model was fabricated using stereolithography 3D printing, and the 3-dimensional mean velocity and turbulent kinetic energy (TKE) field were measured. Results from the reference model showed highly non-uniform flow distribution and high TKE regions. An improved machine room geometry was proposed, which led to an increase in mean flowrate through the condenser by 17.3% and a reduction in high TKE regions by over 77%, potentially resulting in improved energy efficiency and reduced turbulence-induced noise. By increasing the flow rate through the heat exchanger, the fan speed can be reduced while maintaining the same thermal efficiency, thereby lowering the noise level from 29 dB to 25 dB. These findings have implications for the practical application of cooling systems and highlight the potential of MRV for future research in analyzing fan noise and applying MRV to models with built-in fans. This research is being conducted in collaboration with the Vibration Noise Project at the H&A R&D Center of LG Electronics.
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Research Presentation Video
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H. Dong, C. Im, C. Kang, j. Cho, I. Jang and S. Song, 2023, "Investigation of flow behavior in a refrigerator machine room using magnetic resonance velocimetry", International Journal of Heat and Mass Transfer, 214,124446
H. Dong, C. Im, S. Song, "Mean velocity and TKE measurements in a refrigerator machine room using magnetic resonance velocimetry", KSME Conference, 2022, November, 11, Jeju, Korea
H. Dong, C. Im, S. Song, "Mean velocity and TKE measurements in a refrigerator machine room using magnetic resonance velocimetry", APS DFD, 2022, November. 20, Indianapolis, USA
H. Dong, C. Im, I. Jang, S. Song, "Measurement of 3D Velocity and Turbulent Kinetic Energy in a Refrigerator Machine Room Using Magnetic Resonance Velocimetry", ACFM, 2023, August. 10, Beijing, China
H. Dong, C. Im, C. Kang, J. Cho, I. Jang, S. Song, "Analysis of Flow Behavior in a Refrigerator Machine Room Using Magnetic Resonance Velocimetry", FSSIC, 2023, August. 31, Busan, Korea
Noise Reduction in Refrigerator Freezer through MRV-based Structural Modifications
(Visualization of flow and pressure fields in the suction muffler of a reciprocating compressor using MRV)
The Multiscale Heat & Fluid Flow Lab (MFL) applies MRV-based techniques to characterize three-dimensional flow and turbulence structures in refrigerator freezer, with the goal of reducing flow-induced noise and enhancing energy efficiency. This study conducted a comprehensive analysis of a 3/5 scale freezer model, incorporating the cooling system, compartment, and cabinets, all fabricated using stereolithography three-dimensional (3D) printing. By focusing on flow characteristics, 3D mean velocity and turbulent kinetic energy (TKE) fields were measured, identifying regions of non-uniform flow and elevated TKE. To address these issues, structural modifications were introduced in an improved model. These modifications included refining the central structure of the fan chamber, altering inlet geometries, and adding a fillet at the inlet edge. The results were significant: a more uniform flow distribution was achieved, with a 15 percentage-point increase in the effective flow rate through the evaporator’s finned area, a reduction in secondary flow energy in the fan chamber, and a substantial decrease in TKE. Consequently, the improved model demonstrated enhanced energy efficiency and a 3.5 dB reduction in noise. These findings highlight the potential of MRV as an effective tool for analyzing complex flow systems in appliance design. This research is being conducted in collaboration with the Vibration Noise Project at the H&A R&D Center of LG Electronics.
Energy &
Environment
Research Publication
1.
Comparison of compressor flow performance and pressure drop based on MRV
(Visualization of flow and pressure fields in the suction muffler of a reciprocating compressor using MRV)
The Multiscale Heat & Fluid Flow Lab (MFL) applies MRV-based techniques to characterize three-dimensional flow and turbulence structures in suction mufflers, with the goal of comparing flow performance and pressure drop. Two 2:1 scaled models of the suction muffler, including the compressor shell, were fabricated via stereolithography 3D printing. The three-dimensional mean velocity and turbulent kinetic energy (TKE) fields were measured to provide a comprehensive description of the internal flow characteristics, and the omni-directional integration (ODI) method was employed to estimate the internal pressure distribution in the primary flow regions of the suction muffler. The results showed that the pressure drop at the outlet plane in Model 2 was reduced by approximately 44.4% compared to Model 1. Significant flow non-uniformity at both the inlet and outlet, as well as flow separation, recirculation, and high TKE regions within both suction muffler models were identified. These findings provide valuable insights into the complex flow behavior within suction mufflers, establish boundary conditions and experimental benchmarks for validating Reynolds-Averaged Navier-Stokes (RANS) turbulence models, and highlight the potential of MRV measurements for investigating, understanding, and improving the flow performance of suction mufflers. This research is being conducted in collaboration with the Vibration Noise Project at the H&A R&D Center of LG Electronics.
Energy &
Environment
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