On the use of infrared thermography in studies with air curtain devices

Neto, Lpc; Silva, M.C. Gameiro; Costa, J.J.

doi:10.1016/j.enbuild.2006.02.004

Cited by 16 publications

(8 citation statements)

References 1 publication

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“…Due to similarity, the research on nonrecirculating air curtains is helpful. It is mainly related with heat and mass transfer studies, considering the impinging jet of several angles, different initial velocities, temperatures and thicknesses, and generation/suppression of turbulence inside air stream [9][10][11][12][13][14]. Although, due to specific characteristics of air curtains installed in ORDC, researchers carried out two-(2D) and three-(3D) dimensional computational fluid dynamics (CFD) parametric studies.…”

Section: Introductionmentioning

confidence: 99%

Detailed CFD Modelling of Open Refrigerated Display Cabinets

Gaspar

Gonçalves

Pitarma

2012

Modelling and Simulation in Engineering

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A comprehensive and detailed computational fluid dynamics (CFDs) modelling of air flow and heat transfer in an open refrigerated display cabinet (ORDC) is performed in this study. The physical-mathematical model considers the flow through the internal ducts, across fans and evaporator, and includes the thermal response of food products. The air humidity effect and thermal radiation heat transfer between surfaces are taken into account. Experimental tests were performed to characterize the phenomena near physical extremities and to validate the numerical predictions of air temperature, relative humidity, and velocity. Numerical and experimental results comparison reveals the predictive capabilities of the computational model for the optimized conception and development of this type of equipments. Numerical predictions are used to propose geometrical and functional parametric studies that improve thermal performance of the ORDC and consequently food safety.

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Section: Introductionmentioning

confidence: 99%

Detailed CFD Modelling of Open Refrigerated Display Cabinets

Gaspar

Gonçalves

Pitarma

2012

Modelling and Simulation in Engineering

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“…A numerical and experimental evaluation was carried out to understand the reduction of effectiveness due to external lateral flows [26]. A specific study on the behavior of air curtains was developed in [27], where a thermography measurement technique was applied. The temperature profile along the central axis of the jet was displayed, confirming that the optimal working conditions correspond to the minimum of the deflection modulus, as stated in [28].…”

Section: Air Curtains Possible Use In Stentersmentioning

confidence: 99%

Heat Recovery for a Textile Stenter: CFD Analysis of Air Curtain Benefits

et al. 2019

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Modern textile stenters are designed to reduce the inefficiency of the process and to recover the flow stream, which still contains a relatively high energetic value. In recent years, research has focused on the recovery of the energy content of the low-temperature exhaust flow; nonetheless, another important aspect that may increase the efficiency of the process is the reduction of the ambient air suction. In the present research, an innovative way to improve both machine insulation and energy savings, by using preheated air, was numerically evaluated. The proposed solution utilizes an air stream transverse to the fabric (generally called air curtain), either preheated or not, to create soft gates both at the inlet and at the outlet section of the drying machine. Several valuable advantages can be listed when using this solution: reduction of the dispersion of heat and humid polluted air to the work environment, limitation of air ingestion from outside, and effective heat recovery coupled to a uniform temperature profile around the textile fabric. To analyze the insulation capability of the air curtains in terms of mass and energy transfer, a two-dimensional CFD model of the machine was realized. A test matrix including three possible fabric speeds (20, 40 and 60 m/min), three tilt angles (−15°, 0° and 15°), four mass flow rates (0% with no air curtains and 3%, 5% and 7% of the total flow rate through the machine, where the 5% case is equivalent to the flow rate ingested from the ambient) and two temperatures (15 °C and 70 °C) of the plane jets exiting from the air curtains was considered, thus covering a wide range of possible practical applications. The obtained results demonstrate that warm air curtains at both the inlet and outlet are very effective in a fabric speed range up to 40 m/min; at higher fabric speed, entrainment of warm gases from inside the machine at the fabric outlet becomes relevant, and the adoption of a cold air curtain (capable of better insulation) can be recommended in this position.

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“…The DAG velocity and the height/width ratio of the air curtain possess high influence in the air curtain performance [10,13,14,[21][22][23][24]. According to Hayes and Stoecker [25], the deflection modulus, D m (1), describes the ability to provide proper sealing of an ORDC to the surroundings.…”

Section: Influence Of the Fans Velocitymentioning

confidence: 99%

CFD Parametric Studies for Global Performance Improvement of Open Refrigerated Display Cabinets

Gaspar

Gonçalves

Pitarma

2012

Modelling and Simulation in Engineering

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A detailed CFD modelling of an open refrigerated display cabinet has been formulated in a previous study. Some modifications are introduced in order to perform parametric studies dealing with low-cost geometrical and functional characteristics for improvement of the global performance and energy efficiency. The parametric studies are devoted to the analysis of the thermal response and behaviour inside the food conservation space influenced by (1) air flow rate through the evaporator heat exchanger; (2) air curtain behaviour; (3) hole dimensions and distribution of the back panel; (4) discharge and return grilles angles; and (5) flow deflectors inside the internal duct. The analysis of the numerical predictions from the parametric studies allows the development of an optimized model for the conception of an open refrigerated display cabinet with a more adequate configuration. The numerical predictions of the optimized model show lower product temperature and reduced electrical energy consumption, allowing the improvement of the food safety and the energy rationalization of the refrigeration equipment.

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On the use of infrared thermography in studies with air curtain devices

Cited by 16 publications

References 1 publication

Detailed CFD Modelling of Open Refrigerated Display Cabinets

Detailed CFD Modelling of Open Refrigerated Display Cabinets

Heat Recovery for a Textile Stenter: CFD Analysis of Air Curtain Benefits

CFD Parametric Studies for Global Performance Improvement of Open Refrigerated Display Cabinets

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