Experimental heat transfer and isothermal pressure drop data for single-phase water flows in a plate heat exchanger (PHE) with chevron plates are presented. In a single-pass U-type counterflow PHE, three different chevron plate arrangements are considered: two symmetric plate arrangements with β = 30 deg/30 deg and 60 deg/60 deg, and one mixed-plate arrangement with β = 30 deg/60 deg. For water (2 < Pr < 6) flow rates in the 600 < Re < 104 regime, data for Nu and f are presented. The results show significant effects of both the chevron angle β and surface area enlargement factor φ. As β increases, and compared to a flat-plate pack, up to two to five times higher Nu are obtained; the concomitant f, however, are 13 to 44 times higher. Increasing φ also has a similar, though smaller effect. Based on experimental data for Re a 7000 and 30 deg ≤ β ≤ 60 deg, predictive correlations of the form Nu = C1,(β) D1(φ) Rep1(β)Pr1/3(μ/μw)0.14 and f = C2(β) D2(φ) Rep2(β) are devised. Finally, at constant pumping power, and depending upon Re, β, and φ, the heat transfer is found to be enhanced by up to 2.8 times that in an equivalent flat-plate channel.

No abstract

Steady-state heat transfer and pressure drop data for single-phase viscous fluid flows (2 ≤ Re ≤ 400) in a single-pass U-type counterflow plate heat exchanger (PHE) with chevron plates are presented. With vegetable oil as test fluid (130 < Pr < 290), three different plate arrangements are employed: two symmetric (β = 30 deg/30 deg and 60 deg/60 deg) and one mixed (β = 30 deg/60 deg). The effects of chevron angle β, corrugation aspect ratio γ, and flow conditions (Re, Pr, μ/μw on Nu and f characteristics of the PHE are delineated. The results show a rather complex influence of plate surface corrugations on the enhanced thermal-hydraulic behavior. Relative to the performance of equivalent flat-plate packs, chevron plates sustain up to 2.9 times higher heat transfer rates on a fixed geometry and constant pumping power basis, and require up to 48 percent less surface area for the fixed heat load and pressure drop constraint.

No abstract

Aerospace system efficiency improvement and capacity growth has fueled demand for innovative, affordable and scalable thermal management technologies. Recent advancements in additive manufacturing (AM) and materials has extended the thermal design space for heat exchangers, cold plates, heat sinks, and heat pipes. Novel heat transfer enhancement techniques, along with design and system interface innovations, offer attractive cooling solutions for use in numerous aircraft systems. These advances are becoming increasingly relevant in aircraft systems as customers are demanding the use of air-cooling instead of liquid-cooling with minimal impact on overall energy conversion efficiency, installed volume and weight. This paper provides an overview of Boeing-led advances in analysis, design, fabrication and testing of next generation heat transfer devices. A case study is presented to provide insight into a methodology for selection of heat transfer surfaces and design optimization for an air-to-air heat exchanger. Design considerations are presented for additive manufacturing of the thermal management devices using a range of high performance materials including aluminum, titanium, stainless steel, and conductive polymer composites.