A heat exchanger includes: multiple flat tubes that extend in a second direction intersecting a first direction which is an air flow direction and that are disposed at intervals in a third direction that intersects the first direction and the second direction; and multiple plate-like heat transfer fins that extend along the third direction and that are disposed at intervals along the second direction. The heat exchanger causes refrigerant in the flat tubes to exchange heat with the air flow that passes through heat exchange spaces formed by adjacent flat tubes and adjacent heat transfer fins when viewed from the first direction. The heat transfer fins each have a heat transfer fin front side surface that is one main surface, a heat transfer fin back side surface that is the other main surface.

A heat exchanger for use in high pressure environments, such as in a gas turbine engine, includes an outer casing, a tubular element within the outer casing and an inner sleeve within the tubular element. The tubular element has an outer surface and an inner surface. The outer casing and outer surface of the tubular element define a first annular passage through which a first fluid flow path extends. The inner sleeve and inner surface of the tubular element define a second annular passage through which a second fluid flow path extends. The first annular passage is sealed against the outer surface of the tubular element and the second annular passage is sealed within the inner surface of the tubular element.

In one aspect, an apparatus comprises a housing forming an internal cavity and a supercritical fluid enclosed in the internal cavity. The housing is configured to thermally couple to a heat-generating component. The supercritical fluid comprises a fluid in a supercritical state. In addition, the supercritical fluid is configured to transfer heat away from the heat-generating component.

A heat exchanger includes: a plurality of first heat transfer tubes, a plurality of second heat transfer tubes located on leeward side relative to the plurality of first heat transfer tubes, a first distribution unit connecting the first ends of the plurality of first heat transfer tubes and the third ends of the plurality of second heat transfer tubes. The first distribution unit includes a flow rate control unit configured to be capable of switching between a first state and a second state. In the first state, refrigerant flows in the plurality of first heat transfer tubes and the plurality of second heat transfer tubes. In the second state, in only the plurality of first heat transfer tubes, a flow rate of the refrigerant is smaller than a flow rate of the refrigerant in the first state.

A heat exchanger having a plurality of first tubes and second tubes through which a refrigerant passes and which are lengthily formed up and down, each of the first and second tubes being spaced from each other and air flowing between the tubes; and a fin in contact with the first and second tubes, wherein the second tubes are spaced from each other and located at a slipstream of the first tubes in an air-flow direction, a first louver group having a plurality of louvers located between the first tubes and spaced from each other in the air-flow direction and a second louver group having a plurality of louvers located between the second tubes and spaced from each other in the air-flow direction are formed in the fin, wherein some of the louvers of the second louver group are longer toward the slipstream of the air-flow direction.

In a heat exchanger that includes heat-absorbing fins and heat-absorbing tubes, each of which pierces through a corresponding through hole formed by a burring process, when a brazing material held by each of brazing material holding portions is positioned above a corresponding missing portion, formed by removing a part of a burring wall of each of the through holes, melts and penetrates between each of the burring walls and the corresponding heat-absorbing tube, each of the brazing material holding portions is extended above the corresponding missing portion at a predetermined distance. A notched portion concaved downward is positioned on each side of the respective brazing material holding portions.

A microchannel flat tube applicable in a microchannel heat exchanger includes a flat tube body and a row of channels. The row of channels is arranged in the flat tube body along a width direction. The row of channels extends through the flat tube body along a length direction. A cross-section of each channel includes a first width in the width direction and a first height in a thickness direction. The row of channels at least includes a first group of first channels, a second group of second channels and a third group of third channels along the width direction. The first widths of the first channels, the second channels and the third channels decrease at a fixed value, thereby facilitating the control of the thickness of the microchannel flat tube and improving the heat exchange efficiency.

A phase change material (PCM) heat exchanger system for a rocket or other spacecraft is described. The PCM heat exchanger utilizes phase-change material to store heat absorbed from a hot working fluid. The PCM heat exchanger may be configured as an integrated modular double brazed layout that includes folded fins to distribute heat from a working fluid (e.g., hydraulic fluid) to PCM. A modular configuration may enable a heat exchanger system to be scaled up or down by adding or removing modules to meet cooling requirements for particular rockets and their flights.

A heat transfer device includes a heat pipe in which working fluid is enclosed, a heat receiving plate provided on one end side of the heat pipe and a heat radiating fin provided on the other end side of the heat pipe, a first wick and a second wick that transfer working fluid provided on an inner wall surface of the heat pipe, a bent section bent between the one end side and the other end side, and a boundary section between the first wick and the second wick disposed in a lower part in the gravity direction of the bent section of the heat pipe or the heat transfer device. The heat transfer device can improve heat transfer characteristics with a simple configuration.

Corrugated fins that have high heat transfer performance and do not cause clogging even in a gaseous environment in which particulate matter such as dust is present have wall surfaces on which are formed alternating parallel ridges and furrows with an angle of inclination of 10-60?. Defining Wh as the height of the ridges and furrows, Wp as the period of the ridges and furrows, Pf as the period of the corrugated fins, and Tf as the thickness of the plate forming the fins, the following conditions hold.
Wh?0.3674.Math.Wp+1.893.Math.Tf?0.1584,
0.088<(Wh?Tf)/Pf<0.342, and
a.Math.Wp2+b.Math.Wp+c<Wh,
where
a=0.004.Math.Pf.sup.2?0.0696.Math.Pf+0.3642
b=?0.0036.Math.Pf.sup.2+0.0625.Math.Pf?0.5752, and
c=0.0007.Math.Pf.sup.2+0.1041.Math.Pf+0.2333.