Inlet Doors Research Articles

Quality Assessment of Drinking Water from Vending Machines for a Healthier Life

Commercial water vending machines in urban communities are important for consumers because of their convenience and affordability. Therefore, this study investigated the environmental conditions, maintenance, and quality of drinking water distributed through vending machines in an urban community in Thailand. The research sampled 101 drinking water machines in Buriram Municipality, Buriram Province. These machines were assessed for physical characteristics and the surrounding environment and were conducted according to an evaluation form provided by the Ministry of Public Health, Thailand. The findings revealed that 93.07% of the machines had auto coin failures; did not record the date, month, and year of filter changes; and did not display the business license on the cabinet. Additionally, 89.1% of the cabinets had thick dust, 57.43% had damaged or rusted handles on the water inlet door, and 56.44% had algae or rust stains on the water dispenser head. A physiochemical analysis revealed that 83.2% of the machines did not detect the pH levels. Total coliform bacteria and E. coli were not detected in 39.6% and 12.9% of samples, respectively. This study was conducted to develop an application for monitoring the quality of drinking water from vending machines to ensure that standards are met and up-to-date information is provided to help consumers make informed decisions about using clean and safe drinking water from vending machines.

Numerical Analysis of Smoke Spreading in a Medium-High Building under Different Ventilation Conditions

Smoke from fires in residential buildings represents the greatest threat to the life and health of inhabitants and firefighters at the scene of an accident. Therefore, the aim of this study was to reconstruct a numerical model for the estimation of smoke spread in a medium-high building under different ventilation conditions. Here, the three-dimensional geometry of a designated medium-high building was reconstructed and an exit door in the basement was specified as a smoke inlet; a window in the upper part was marked as outlet; and an entrance door, which allowed the outside air to enter the building after opening, was designated as an inlet door. The initial simulation, in which no air could enter the building, predicted the time taken for the staircase to become filled with smoke. In a second simulation, the entrance door was a fresh air inlet. The results showed that, for the analyzed building, rapid use of the mechanical ventilation can shorten the time of operations and improve their safety.

Numerical modeling on installed performance of turbofan engine with inlet ejector

In order to consider the capacity of aircraft infrared stealth, a turbofan engine with inlet ejector nozzle is derived for flight mission analysis. The turbofan engine is equipped with an auxiliary inlet door that utilizes the inlet bypass flow to ejector the nozzle and increase the engine installed thrust. Firstly, on the basis of the quasi one-dimensional flow theory, the ejector nozzle model is established to analyze its performance effect on the engine. Secondly, a backward infrared radiation intensity prediction method for exhaust system is proposed. Finally, during the analysis of engine installed performance, the supersonic inlet drag is considered. The numerical simulations results indicated that, compared with the conventional turbofan engine, the turbofan engine with inlet ejector not only reduces the infrared radiation and specific fuel consumption, but also increases the engine installed thrust, which improves the engine performance significantly.

Computational Study of Indoor Pollutant Dispersion of an Apartment

Objectives: Indoor Air Quality (IAQ) is very important for the health of human beings. Proper ventilation of apartment can improve IAQ. The objective of the study is to analyse the pollutant dispersion behaviour inside the fluid domain at fixed boundary conditions. Methods/Statistical Analysis: A 2BHK apartment has been taken for study. The fluid domain of apartment has been simulated in the Computational Fluid Dynamics (CFD) software “ANSYS Fluent 16.2”. Four inlet doors, four inlet windows, one outlet door, one outlet window and two ventilations from toilets were taken in the apartment. Seven inlet pollutant sources at the middle of the bottom of each enclosed area i.e. drawing/dining room, master bedroom, bedroom 1, kitchen, toilet 1 and toilet 2 have been considered. The methane gas is selected as the pollutant in the study. The k-epsilon (2 equations) model has been used and methane-air mixture has been taken for species transport. Findings: The methane mass fraction has been studied at different planes and at different locations of the domain. It was observed that the pollutant dispersion phenomena were varying at different locations and with this the highest methane mass fraction zone have been discussed. Application/Improvements: Simulated model can be useful in urban management and planning to find the best geometrical configurations of infrastructure, especially residential, to achieve proper and effective ventilations. Present model can also be more effective with environmental wind tunnel validations.

Experimental and numerical studies of the aeroacoustics of axisymmetric supersonic inlets

A series of experiments were conducted at an outdoor facility to evaluate the aerodynamic and acoustic performance of a supersonic inlet with a modified auxiliary door geometry. A 1/14 scale model of an axisymmetric, mixed-compression, supersonic inlet designed for civil transportation (P-inlet) was used in conjunction with a 10.4 cm (4.1 in) turbofan engine simulator, to test a new auxiliary door geometry designed to reduce engine fan noise radiated to the forward sector. The flow distortion at the fan face was reduced by modifying the auxiliary inlet doors. The new door geometry uses door passages with increased circumferential span to improve the distribution of the flow entering through the doors. To provide a basis for comparison, a baseline inlet with an auxiliary door geometry representative of the original designs was also tested. The results show that the new door geometry is successful in reducing circumferential distortion of the flow Mach number near the fan face by 30% compared to the baseline configuration. In addition, far field radiation of the blade passing frequency tone and overall noise is reduced by an average of 4 dB (SPL)in the forward sector (0° to 110° from the inlet axis). A 3-D, viscous numerical simulation of the baseline door configuration reveals a large region of flow separation downstream of the auxiliary door. This flow separation leads to a significant increase in circumferential distortion at the fan face.

Fan Noise Reduction From a Supersonic Inlet During Simulated Aircraft Approach

A series of experiments was conducted to investigate the radiation of fan noise from a supersonic inlet during a simulated aircraft approach. A scaled-down model of an axisymmetric, mixed-compression, supersonic inlet (P-inlet) was used in conjunction with a 10.4 cm (4.1 in) diameter turbofan engine simulator as the noise source. The tests were conducted at an outdoor facility under static conditions. The main goal of the experiment was to reduce the forward radiating fan noise by modifying the auxiliary inlet doors. The modified doors are designed to reduce the inlet distortion to the fan face. In addition, the new door design also uses a converging flow passage in order to take advantage of the noise attenuation due to the choking effect at the auxiliary door. The simulator was tested at 60 percent design speed in an attempt to match the simulator noise source to that of a real aircraft engine on approach. Both aerodynamic and acoustic measurements were taken in the experiments. The results show that when compared to the original design, the modified auxiliary inlet doors reduced the circumferential inlet distortion to the fan face by a factor of two. The key result is that the blade passing frequency tone has been decreased by an average of 6 dB in the forward sector for the modified door design. Results from the closed auxiliary inlet door case are also presented to provide additional comparisons.

Low flight speed fan noise from a supersonic inlet

A model supersonic inlet with auxiliary inlet doors and boundary-layer bleeds was acoustically tested in simulated low speed flight up to Mach 0 2 in the NASA Lewis 9x15 anechoic wind tunnel and statically in the NASA Lewis anechoic chamber A JT8D refan model was used as the noise source. Data were also taken for a CTOL inlet and an annular inlet with simulated centerbody support struts Inlet operation with open auxiliary doors increased the blade passage tone by about 10 clB relative to the closed door configuration although noise radiation was primarily through the main inlet rather than the doors. Numerous strong spikes in the noise spectra were associated with the bleed system and were strongly affected by the centerbody location. The supersonic inlet appeared to suppress multiple pure tones (MPTs) at or near the fan source Inlet length and the presence of support struts were shown not to cause this MPT suppression

An experimental investigation of VTOL lift- engine inlet.

Tests of VTOL lift-engine plain inlets and inlets with scoop-type doors were conducted in the NASA Anies 40- by 80-ft wind tunnel using the Ames Lift Engine Pod containing five YJ85 engines. The objectives were to determine inlet/door performance characteristics during lift-engine operation and to establish engine start and acceleration characteristics during transition. Over-all inlet pressure distortion levels were, in general, lower than the nominal acceptable level of 10%. Acceptable inlet total pressure recoveries were achieved, and considerable improvement in engine windmilling characteristics was observed with the inlet doors. Results also showed the feasibility of windmill starting of lift engines equipped with scoop-type inlet doors at landing transition speeds between 200 and 240 knots.