Patent Application
20140299303
The present inventive concept relates generally to a heat exchanger, and more particularly, to a cooling tube included in a jet aircraft heat exchanger.
Commercial jet aircrafts typically include a one or more galley areas having one or more cooling compartments where food and beverages are stored. The cooling compartments include cooling units to control the temperature within the compartment. Accordingly, the food and beverages stored in the cooling compartment may be cooled.
The galley cooling unit includes a heat exchanger to remove heat from within the compartment. For example, hot circuit air flows across an outer surface of tubes containing a cooled liquid coolant. Conventional heat exchangers, such as a liquid-to-air heat exchanger, include one or more cooling tubes to flow liquid therethrough. Heat from within the compartment may be transferred to the liquid flowing through the cooling tubes. The heat of the liquid is ultimately removed and rejected from the aircraft using an additional fluid conditioning system. The shape of the cooling tube may control the amount of heat removed from the liquid, i.e., the heat transfer rate, and the fluid pressure drop across the heat exchanger.
According to one embodiment of the present inventive concept, a channel tube includes a body having first and second surfaces extending between first and second opposing ends to define a tube width. The first and second surfaces are separated from each other by a distance defining a tube height. A plurality of ports extend through the body and between the first and second surfaces to define a fluid path extending in a direction of the tube width. Each port defines a plurality of walls and a plurality of ribs having a thermal conductive surface to transfer heat therethrough. A first wall extends in a direction of the tube width. The second wall extends in a direction of the tube width and is disposed opposite the first wall. At least one rib is integrally formed between the first and second walls and extends perpendicular thereto.
The subject matter which is regarded as the inventive concept is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features of the inventive concept are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Referring to
The channel tubes 112 deliver the liquid coolant from the inlet 102 to the outlet 104. The liquid coolant may comprise a mixture of approximately 60 percent (%) of propylene glycol and 40% water. Air may interact with the heat exchanger assembly 100 through air fin 116 such that heat is transferred from the air to the liquid coolant, thereby cooling the air. The heated liquid flows through the channel tubes 112 undergoing three passes in a cross-counter flow configuration in the process before exiting through outlet 104. Heat may be removed from the liquid cooling loop by downstream equipment.
Referring now to
The plurality of ports 114 are formed through the body of the channel tube 112 and between the top and bottom surfaces 116,118. Each port 114 extends along the width of the channel tube 112 to convey liquid between the inlet 102 and the outlet 104 of the heat exchanger 100. In one embodiment, the ports 114 are approximately square-shaped. In at least one embodiment, the corners of the ports 114 may be curved to form a square with rounded corners. Alternatively, the ports 114 are rectangular-shaped to define a port height-to-port width ratio. The port height-to-port width ratio may be expressed as port height/port width=ratio. In at least one embodiment, the port height-to-port width ratio is expressed as 0.100 inches/0.0594 inches=1.6835 inches).
In at least one embodiment, the curved ends 122, 124 may define an adjacent port 114 having a semi-circular shape. The width of the semi-circular-shaped end ports (WSEMICIRC) are approximately 0.0594 inch (0.150876 cm). The end ports have a radius of curvature.
Each port 114 defines a first wall, e.g., a top wall 128, a second wall, e.g. a bottom wall 130, and at least one rib, e.g., a center rib 132. The center rib 132 is formed between each adjacent port 114 and extends between the top and bottom walls 128,130. The top and bottom walls 128, 130 have a height (HTTOP, HTBOTTOM) of approximately 0.014 inches (approximately 0.036 cm). In at least one embodiment, the center rib 132 has a width (WCENTER) of approximately 0.010 inches (approximately 0.0254 cm). The center rib 132 is not limited to the aforementioned width, and may have a width ranging from approximately 0.0085 inches (approximately 0.0216 cm) to approximately 0.0115 inches (approximately 0.0292 cm). The top wall 128, bottom wall 130, and center rib 132 are formed integrally to one another. Accordingly, dimensions of the walls and ribs define the overall thickness of each port 114. The number of walls and ribs, width of the port, height of the port, rib thickness, wall thickness, tube material controls the rate of heat transferred to the liquid from the air circuit of the heat exchanger. That is, the rate at which heat is added to the liquid flowing at a set flow rate may be controlled by varying each of the described tube dimensions (rib thickness, wall thickness, tube width, number of ports, port width, port height) independent of modifications to the parameters on the air circuit of the heat exchanger. Accordingly, the channel tube 112 may be sized to meet system performance and pressure drop requirements. In at least one embodiment, the ports 114 have a width (WPORT) of approximately 0.0594 inches (approximately 0.150876 cm+/−tolerances) and a height (HTPORT) of approximately 0.100 inches (approximately 0.254 cm+/−tolerances).
The plurality of walls and ribs provide a heat transfer surface, which contacts the liquid flowing through the ports 114. Accordingly, heat is transferred from the liquid through the walls and ribs and out of the channel tubes 112. The rate of heat transfer from the channel tube 112 and the pressure realized by the heat exchanger 100 may be controlled based on the number of ports 114. Reducing the number of ports 114 (e.g., providing 10 ports) reduces the secondary heat transfer area of each tube 112 and decreases the fluid pressure drop, while increasing the number of ports 114, (e.g., providing 18 ports) increases the secondary heat transfer area and increases the fluid pressure drop. Therefore, the heat transfer primary and secondary surface area and fluid pressure drop provided by the channel tube 112 may be controlled based on the number of ports 114 and the design of the corresponding ribs and wall thicknesses, number of ports, the port height, and the port width.
While various embodiments of the inventive concept had been described, it will be understood that those skilled in the art, both now and in the future, may make various modifications to the embodiments which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.
