Numerical Study on Long-Distance Heating System Based on High-Velocity Jet at Ambient Temperature for Induced Air Supply
Abstract
1. Introduction
2. Concept of the Induced Air Supply System
3. Method
3.1. Numerical Simulation
3.1.1. Computational Domain and Grid Distribution
3.1.2. Boundary Conditions
3.1.3. Governing Equations and Computational Solution
3.2. Evaluation Parameters
3.2.1. Thermal Jet Flow Characteristics
- Axial center temperature (Tcenter)
- 2.
- Dimensionless deflection height (z*)
- 3.
- Local Archimedes number (Ary)
3.2.2. Target Area Heating Performance
- Heating gain ()
- 2.
- Draught rate ()
3.3. Case Description
4. Model Validation
4.1. Grid Independence Verification
4.2. CFD Setup Verification
5. Results and Discussion
5.1. Effect of Induced Airflow
5.2. Characterization of the Flow Field of an Induced Air Supply System
5.2.1. Thermal Jet Trajectory and Deflection Height
5.2.2. Thermal Jet Axial Center Temperature
5.3. Heating Gain of Induced Air Supply System
5.4. Draught Rate of the Induced Air Supply System
6. Conclusions
- (1)
- The induced airflow significantly prolongs the jet stabilization zone and delays the position where the thermal jet floats up. Compared with the single thermal jet, the jet stabilization zone of the induced air supply system can be extended by up to 10 D; under the same induced airflow flow rate, the greater the induced air velocity, the wider the control range of the thermal jet.
- (2)
- The induced airflow effectively improves the phenomenon of upward deflection of the thermal jet and extends the horizontal transport distance of the thermal flow. The induced airflow can inhibit the transformation of the thermal jet from the transition zone to the buoyancy-dominated zone. Compared with a single thermal jet, the deflection of the induced air supply system can be reduced by up to 98.7% at long distances compared to a single thermal jet. Under the same induced airflow flow rate, a larger induced airflow velocity has a more significant inhibitory effect on the deflection of the thermal jet.
- (3)
- The induced airflow can inhibit the mixing of the thermal jet with the surrounding fluid and affect the axial center temperature of the thermal jet. Compared with the single thermal jet, the axial center temperature of the induced air supply system at a close distance (y/D = 7.5) can be increased by 49.3%; a larger induced airflow flow rate can reduce the axial center temperature attenuation of the induced air supply condition from 20.6 K to 7.1 K.
- (4)
- The comprehensive heating performance of the induced air supply system in the entire space is better than that of the single thermal jet. It is necessary to consider the comprehensive impact of jet deflection and axial center temperature on the target area at the same time; the larger the induced airflow rate, the more uniform the thermal environment of the entire heating process. For the target area at a close distance (y/D = 7.5), the single thermal jet air supply can be used; when heating at a medium distance or above (y/D ≥ 15), it is possible to consider increasing the induced airflow velocity first to obtain a higher heating gain.
- (5)
- For the discomfort caused by excessive air supply velocity in the induced air supply system, the overall draught rate in the target area can be improved by adjusting the induced airflow or thermal jet parameters, but at the same time, the heating gain will be reduced.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
- EIA. International Energy Outlook. Available online: www.eia.gov/ieo (accessed on 11 October 2023).
- Szczepanik-Scislo, N.; Flaga-Maryan’czyk, A. Indoor air quality modelling and measurements of a studio apartment with a mechanical exhaust system. E3S Web Conf. 2018, 44, 171. [Google Scholar] [CrossRef]
- Szczepanik-Scislo, N.; Scislo, L. Air leakage modelling and its influence on the air quality inside a garage. E3S Web Conf. 2018, 44, 172. [Google Scholar] [CrossRef]
- Liddament, M.W. A review of ventilation and the quality of ventilation air. Indoor Air 2000, 10, 193–199. [Google Scholar] [CrossRef]
- Khan, A.; Bradshaw, C.R. Quantitative comparison of the performance of vapor compression cycles with compressor vapor or liquid injection. Int. J. Refrig. 2023, 154, 386–394. [Google Scholar] [CrossRef]
- Pérez-Lombard, L.; Ortiz, J.; Pout, C. A review on buildings energy consumption information. Energy Build. 2008, 40, 394–398. [Google Scholar] [CrossRef]
- Szczepanik-Scislo, N.; Scislo, L. Dynamic Real-Time Measurements and a Comparison of Gas and Wood Furnaces in a Dual-Fuel Heating System in Order to Evaluate the Occupants’ Safety and Indoor Air Quality. Buildings 2023, 13, 2125. [Google Scholar] [CrossRef]
- Cheng, F.; Li, Y.; Wu, Y.; Cheng, Y.; Lin, Z. Experimental study of air distribution and heating performances of deflection ventilation. Energy Build. 2023, 282, 112800. [Google Scholar] [CrossRef]
- Ye, X.; Zhu, H.; Kang, Y.; Zhong, K. Heating energy consumption of impinging jet ventilation and mixing ventilation in large-height spaces: A comparison study. Energy Build. 2016, 130, 697–708. [Google Scholar] [CrossRef]
- Szczepanik-Scislo, N.; Antonowicz, A.; Scislo, L. PIV measurement and CFD simulations of an air terminal device with a dynamically adapting geometry. SN Appl. Sci. 2019, 1, 370. [Google Scholar] [CrossRef]
- Szczepanik-Scislo, N. Improving Household Safety via a Dynamic Air Terminal Device in Order to Decrease Carbon Monoxide Migration from a Gas Furnace. Int. J. Environ. Res. Public Health 2022, 19, 1676. [Google Scholar] [CrossRef]
- Ye, X.; Kang, Y.; Zuo, B.; Zhong, K. Study of factors affecting warm air spreading distance in impinging jet ventilation rooms using multiple regression analysis. Build. Environ. 2017, 120, 1–12. [Google Scholar] [CrossRef]
- Hu, J.; Wang, Y.; Wang, D.; Song, J. Impacts of low atmospheric pressure on distribution of indoor hot air jet in plateau area. Indoor Built Environ. 2022, 31, 2447–2466. [Google Scholar] [CrossRef]
- Krajcik, M.; Simone, A.; Olesen, B.W. Air distribution and ventilation effectiveness in an occupied room heated by warm air. Energy Build. 2012, 55, 94–101. [Google Scholar] [CrossRef]
- Kabanshi, A.; Sandberg, M. Entrainment and its implications on microclimate ventilation systems: Scaling the velocity and temperature field of a round free jet. Indoor Air 2019, 29, 331–346. [Google Scholar] [CrossRef]
- Wang, Y.; Huang, Y.; Zhou, Y.; Shu, Y.; Liu, J. Experimental study on one-side confined jets from a parallel-flow outlet in a push-pull ventilation system. Indoor Built Environ. 2015, 24, 73–86. [Google Scholar] [CrossRef]
- Wang, H.; Tang, X.; Huang, C. Investigating ventilation system performance in large space building: A nozzle primary air supply with secondary airflow-relay system. Sci. Technol. Built Environ. 2017, 23, 296–306. [Google Scholar] [CrossRef]
- Wang, H.; Huang, C.; Cui, Y.; Zhang, Y. Experimental study on the characteristics of secondary airflow device in a large enclosed space building. Energy Build. 2018, 166, 347–357. [Google Scholar] [CrossRef]
- Zhu, S.; Cai, W.; Spengler, J.D. Control of sleep environment of an infant by wide-cover type personalized ventilation. Energy Build. 2016, 129, 69–80. [Google Scholar] [CrossRef]
- Cao, Z.; Wang, R.; Zhai, C.; Wang, Y.; Zhao, T.; Wu, S. Flow characteristics and formation optimization of vortex ring air supply. Indoor Air 2022, 32, e13096. [Google Scholar] [CrossRef]
- Zhai, C.; Wang, Y.; Cao, Z.; Zhao, T.; Wang, R.; Zhang, C.; Wu, S. Effect of thermal buoyancy on vortex ring air supply mode. Build. Environ. 2022, 221, 109257. [Google Scholar] [CrossRef]
- Wang, X.; Liu, Y.; Song, C.; Gao, L. Characteristics of oxygenic-thermal coupled jet driven by concentration difference and temperature difference at high altitudes. Build. Environ. 2023, 228, 109897. [Google Scholar] [CrossRef]
- Song, C.; Yang, X.; Liu, Y.; Wang, X. Diffusion characteristics of vertical oxygenic-thermal coupled jet and indoor oxygenic-thermal environment regulation in high-altitude areas. J. Build. Eng. 2024, 93, 109797. [Google Scholar] [CrossRef]
- Saïd, M.N.A.; MacDonald, R.A.; Durrant, G.C. Measurement of thermal stratification in large single-cell buildings. Energy Build. 1996, 24, 105–115. [Google Scholar] [CrossRef]
- Espinosa, F.A.D.; Glicksman, L.R. Determining thermal stratification in rooms with high supply momentum. Build. Environ. 2017, 112, 99–114. [Google Scholar] [CrossRef]
- Chen, H.; Moshfegh, B.; Cehlin, M. Computational investigation on the factors influencing thermal comfort for impinging jet ventilation. Build. Environ. 2013, 66, 29–41. [Google Scholar] [CrossRef]
- Zhang, S.; Lin, Z.; Ai, Z.; Wang, F.; Cheng, Y.; Huan, C. Effects of operation parameters on performances of stratum ventilation for heating mode. Build. Environ. 2019, 148, 55–66. [Google Scholar] [CrossRef]
- Zhang, S.; Cheng, F.; Zhang, X.; Lin, Z.; Cheng, Y. Cooling effect of air movement of advanced air distribution under heating mode: Experimental analyses of stratum ventilation. Build. Environ. 2023, 231, 110041. [Google Scholar] [CrossRef]
- Fan, Y.; Li, X.; Yan, Y.; Tu, J. Overall performance evaluation of underfloor air distribution system with different heights of return vents. Energy Build. 2017, 147, 176–187. [Google Scholar] [CrossRef]
- Yu, Y.; Xia, Y.; Xu, Y.; Gao, J. Aerodynamic sealing using a segmented recirculating horizontal air curtain for buoyancy-driven flows in doorways. Build. Environ. 2024, 247, 111028. [Google Scholar] [CrossRef]
- Yang, B.; Liu, P.; Liu, Y.; Wang, F. Performance evaluation of ductless personalized ventilation combined with impinging jet ventilation. Appl. Therm. Eng. 2023, 222, 119915. [Google Scholar] [CrossRef]
- Duan, T.; Ye, X.; Du, P.; Qi, H.; Kang, Y.; Zhong, K. Study of indoor local thermal comfort for impinging jet ventilation combined with ductless personalized ventilation under different cooling loads. Build. Environ. 2024, 265, 112013. [Google Scholar] [CrossRef]
- Fernandez, K.B.; Yoo, S.-J.; Kuga, K.; Ito, K. Toward occupant-centric system: Multicriteria optimization of hybrid displacement-personalized ventilation system using computational fluid dynamics with computer-simulated person. Build. Environ. 2024, 262, 111837. [Google Scholar] [CrossRef]
- Liu, X.; Liu, X.; Zhang, T. Influence of air-conditioning systems on buoyancy driven air infiltration in large space buildings: A case study of a railway station. Energy Build. 2020, 210, 109781. [Google Scholar] [CrossRef]
- Kanagalingam, S.; William, Y.E. Assessment of Computational Fluid Dynamics Reynolds-Averaged Navier–Stokes Models for Bluff Bodies Aerodynamics. SAE Int. J. Commer. Veh. 2023, 16, 403–419. [Google Scholar] [CrossRef]
- Zhai, Z.J.; Zhang, Z.; Zhang, W.; Chen, Q.Y. Evaluation of various turbulence models in predicting airflow and turbulence in enclosed environments by CFD: Part 1—Summary of prevalent turbulence models. Sci. Technol. Built Environ. 2007, 13, 853–870. [Google Scholar]
- Khan, A.; Irfan, M.; Niazi, U.M.; Shah, I.; Legutko, S.; Rahman, S.; Alwadie, A.S.; Jalalah, M.; Glowacz, A.; Khan, M.K.A. Centrifugal compressor stall control by the application of engineered surface roughness on diffuser shroud using numerical simulations. Material 2021, 14, 2033. [Google Scholar] [CrossRef]
- Shih, T.-H.; Liou, W.W.; Shabbir, A.; Yang, Z.; Zhu, J. A new k-ε eddy viscosity model for high reynolds number turbulent flows. Comput. Fluids 1995, 24, 227–238. [Google Scholar] [CrossRef]
- Shaheed, R.; Mohammadian, A.; Gildeh, H.K. A comparison of standard k-ε and realizable k-ε turbulence models in curved and confluent channels. Environ. Fluid Mech. 2019, 19, 543–568. [Google Scholar] [CrossRef]
- Goodfellow, H.D.; Kosonen, R. Industrial Ventilation Design Guidebook: Volume 1: Fundamentals; Academic Press: Cambridge, MA, USA, 2020; pp. 268–271. [Google Scholar]
- ISO 7730:2005; Ergonomics of the Thermal Environment-Analytical Determination and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria. ISO: Geneva, Switzerland, 2005.
- GB 33658-2017; Thermal Comfort Requirements and Evaluation for Indoor Environment (in Chinese). Standards Press of China: Beijing, China, 2017.
- Roache, P.J. Perspective: A method for uniform reporting of grid refinement studies. J. Fluids Eng. 1994, 116, 405–413. [Google Scholar] [CrossRef]
- Hossain, M.; Rodi, W. A turbulence model for buoyant flows and its application to vertical buoyant jets. In Turbulent Buoyant Jets and Plumes; Elsevier: Amsterdam, The Netherlands, 1982; pp. 121–178. [Google Scholar]
- Michas, S.N.; Papanicolaou, P.N. Horizontal round heated jets into calm uniform ambient. Desalination 2009, 248, 803–815. [Google Scholar] [CrossRef]
- Koestel, A. Paths of Horizontally Projected Heated and Chilled Air Jet. ASHVE Trans. 1955, 61, 213–232. [Google Scholar]
Region | Boundary Type | Boundary Conditions |
---|---|---|
Inlet | Velocity inlet | Temperature: 283.15 K/323.15 K/333.15 K |
Other outer boundaries | Pressure outlet | Backflow Total Temperature: 283.15 K |
Floor and rear wall | Wall | Non-slip, adiabatic |
Project Settings | Operating Conditions |
---|---|
Solver | Implicit solution based on pressure |
Pressure-velocity coupling mode | SIMPLE |
Momentum, turbulent kinetic energy, turbulent dissipation rate and energy | Second order upwind |
Pressure | PRESTO! |
Air density | Incompressible ideal gas |
Operating environment temperature | 283.15 K |
Sa:St | Jet Inlet Type | Case | Ambient Air Jet (Ta = 283.15 K) | Thermal Air Jet | Qa (m3/s) | |
---|---|---|---|---|---|---|
Va (m/s) | Vt (m/s) | Tt (K) | ||||
0:1 | 0 | / | 5 | 323.15 | 0 | |
0.25:1 | 1-1 | 5 | 5 | 323.15 | 0.2 | |
1-2 | 7.5 | 5 | 323.15 | 0.3 | ||
1-3 | 10 | 5 | 323.15 | 0.4 | ||
0.5:1 | 2-1 | 5 | 5 | 323.15 | 0.4 | |
2-2 | 7.5 | 5 | 323.15 | 0.6 | ||
2-3 | 10 | 5 | 323.15 | 0.8 | ||
2-4 | 10 | 4 | 333.15 | 0.8 | ||
1:1 | 3-1 | 5 | 5 | 323.15 | 0.8 | |
3-2 | 7.5 | 5 | 323.15 | 1.2 | ||
3-3 | 10 | 5 | 323.15 | 1.6 |
Item | Grid Number | r | Vave (y/D = 7.5) | Tave (y/D = 7.5) | Vave (y/D = 15) | Tave (y/D = 15) |
---|---|---|---|---|---|---|
203/420 × 106 | 1.67 | 0.76% | 0.11% | 12.20% | 0.06% | |
GCI | 203/420 × 106 | 1.67 | 1.27% | 0.18% | 20.47% | 0.11% |
420/836 × 106 | 1.29 | 0.07% | 0.01% | 2.13% | 0.02% | |
GCI | 420/836 × 106 | 1.29 | 0.32% | 0.05% | 9.63% | 0.09% |
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Zhang, J.; Bai, Y.; Cao, Z.; Yang, Z.; Lv, W. Numerical Study on Long-Distance Heating System Based on High-Velocity Jet at Ambient Temperature for Induced Air Supply. Buildings 2025, 15, 979. https://doi.org/10.3390/buildings15060979
Zhang J, Bai Y, Cao Z, Yang Z, Lv W. Numerical Study on Long-Distance Heating System Based on High-Velocity Jet at Ambient Temperature for Induced Air Supply. Buildings. 2025; 15(6):979. https://doi.org/10.3390/buildings15060979
Chicago/Turabian StyleZhang, Jingwen, Yuqing Bai, Zhixiang Cao, Zefang Yang, and Wenchao Lv. 2025. "Numerical Study on Long-Distance Heating System Based on High-Velocity Jet at Ambient Temperature for Induced Air Supply" Buildings 15, no. 6: 979. https://doi.org/10.3390/buildings15060979
APA StyleZhang, J., Bai, Y., Cao, Z., Yang, Z., & Lv, W. (2025). Numerical Study on Long-Distance Heating System Based on High-Velocity Jet at Ambient Temperature for Induced Air Supply. Buildings, 15(6), 979. https://doi.org/10.3390/buildings15060979