Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms
Displacement ventilation, where cool external air enters a room through low-level vents and warmer air leaves through high-level vents, is characterised by vertical gradients in pressure arising from the warmer indoor temperatures. Models usually assume that horizontal variations of temperature diff...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Cambridge University Press
2023-01-01
|
| Series: | Flow |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S2633425923000119/type/journal_article |
| _version_ | 1797799761004199936 |
|---|---|
| author | Carolanne V.M. Vouriot Thomas D. Higton P.F. Linden Graham O. Hughes Maarten van Reeuwijk Henry C. Burridge |
| author_facet | Carolanne V.M. Vouriot Thomas D. Higton P.F. Linden Graham O. Hughes Maarten van Reeuwijk Henry C. Burridge |
| author_sort | Carolanne V.M. Vouriot |
| collection | DOAJ |
| description | Displacement ventilation, where cool external air enters a room through low-level vents and warmer air leaves through high-level vents, is characterised by vertical gradients in pressure arising from the warmer indoor temperatures. Models usually assume that horizontal variations of temperature difference are small in comparison and are, therefore, unimportant. Small-scale laboratory experiments and computational fluid dynamics were used to examine these flows, driven by a uniformly heated floor. These experiments and simulations show that the horizontal variations of temperature difference can be neglected for predictions of the bulk ventilation rate; however, they also evidence that these horizontal variations can be significant and play a critical role in establishing the pattern of flow within the room – this renders the horizontal position of the low- and high-level vents (relative to one another) important. We consider two cases: single-ended (where inlet and outlet are at the same end of the room) and opposite-ended. In both cases the ventilation flow rate is the same. However, in the opposite-ended case a dead zone is established in the upper part of the room which results in significant horizontal variations. We consider the formation of this dead zone by examining the streamline patterns and the age of air within the room. We discuss the implications for occupant exposure to pollutants and airborne disease. |
| first_indexed | 2024-03-13T04:24:48Z |
| format | Article |
| id | doaj.art-5cbfffa9822243548ad1a8cfdb8e9e10 |
| institution | Directory Open Access Journal |
| issn | 2633-4259 |
| language | English |
| last_indexed | 2024-03-13T04:24:48Z |
| publishDate | 2023-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Flow |
| spelling | doaj.art-5cbfffa9822243548ad1a8cfdb8e9e102023-06-20T07:10:33ZengCambridge University PressFlow2633-42592023-01-01310.1017/flo.2023.11Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within roomsCarolanne V.M. Vouriot0Thomas D. Higton1P.F. Linden2https://orcid.org/0000-0002-8511-2241Graham O. Hughes3Maarten van Reeuwijk4https://orcid.org/0000-0003-4840-5050Henry C. Burridge5https://orcid.org/0000-0002-0719-355XDepartment of Civil and Environmental Engineering, Skempton Building, South Kensington Campus, Imperial College London, London SW7 2BX, UK Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Rd, Cambridge CB3 0WA, UKDepartment of Civil and Environmental Engineering, Skempton Building, South Kensington Campus, Imperial College London, London SW7 2BX, UKDepartment of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Rd, Cambridge CB3 0WA, UKDepartment of Civil and Environmental Engineering, Skempton Building, South Kensington Campus, Imperial College London, London SW7 2BX, UKDepartment of Civil and Environmental Engineering, Skempton Building, South Kensington Campus, Imperial College London, London SW7 2BX, UKDepartment of Civil and Environmental Engineering, Skempton Building, South Kensington Campus, Imperial College London, London SW7 2BX, UKDisplacement ventilation, where cool external air enters a room through low-level vents and warmer air leaves through high-level vents, is characterised by vertical gradients in pressure arising from the warmer indoor temperatures. Models usually assume that horizontal variations of temperature difference are small in comparison and are, therefore, unimportant. Small-scale laboratory experiments and computational fluid dynamics were used to examine these flows, driven by a uniformly heated floor. These experiments and simulations show that the horizontal variations of temperature difference can be neglected for predictions of the bulk ventilation rate; however, they also evidence that these horizontal variations can be significant and play a critical role in establishing the pattern of flow within the room – this renders the horizontal position of the low- and high-level vents (relative to one another) important. We consider two cases: single-ended (where inlet and outlet are at the same end of the room) and opposite-ended. In both cases the ventilation flow rate is the same. However, in the opposite-ended case a dead zone is established in the upper part of the room which results in significant horizontal variations. We consider the formation of this dead zone by examining the streamline patterns and the age of air within the room. We discuss the implications for occupant exposure to pollutants and airborne disease.https://www.cambridge.org/core/product/identifier/S2633425923000119/type/journal_articleNatural ventilation of buildingsBuoyancy driven flowsHorizontal convection |
| spellingShingle | Carolanne V.M. Vouriot Thomas D. Higton P.F. Linden Graham O. Hughes Maarten van Reeuwijk Henry C. Burridge Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms Flow Natural ventilation of buildings Buoyancy driven flows Horizontal convection |
| title | Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| title_full | Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| title_fullStr | Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| title_full_unstemmed | Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| title_short | Uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| title_sort | uniformly distributed floor sources of buoyancy can give rise to significant spatial inhomogeneities within rooms |
| topic | Natural ventilation of buildings Buoyancy driven flows Horizontal convection |
| url | https://www.cambridge.org/core/product/identifier/S2633425923000119/type/journal_article |
| work_keys_str_mv | AT carolannevmvouriot uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms AT thomasdhigton uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms AT pflinden uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms AT grahamohughes uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms AT maartenvanreeuwijk uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms AT henrycburridge uniformlydistributedfloorsourcesofbuoyancycangiverisetosignificantspatialinhomogeneitieswithinrooms |