대수평균온도차(LMTD)는 열교환기, 특히 대향류 및 병류 배열에서 열 전달에 대한 유효 평균 온도차입니다. 이는 각 끝단의 고온 유체와 저온 유체 사이의 온도차의 대수 평균입니다. LMTD는 다음 공식으로 계산됩니다. [latex]Delta T_{LM} = frac{Delta T_A – Delta T_B}{ln(Delta T_A / Delta T_B)}[/latex].
로그 평균 온도 차이(LMTD)
1910
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The LMTD method is a cornerstone of heat exchanger analysis. It arises from the integration of the heat transfer rate equation along the length of the exchanger, assuming constant fluid properties and overall heat transfer coefficient. The fundamental heat transfer equation is [latex]Q = U A \Delta T_{LM}[/latex], where Q is the rate of heat transfer, U is the overall heat transfer coefficient, and A is the heat transfer surface area. The LMTD correctly accounts for the non-linear temperature profile of the fluids as they flow through the exchanger. For a counter-current flow exchanger, [latex]\Delta T_A[/latex] and [latex]\Delta T_B[/latex] are the temperature differences at the two ends of the exchanger. For a parallel flow exchanger, the same formula applies, but the temperature differences are calculated differently based on the inlet and outlet positions. The counter-flow arrangement is generally more efficient as it yields a higher LMTD for given inlet and outlet temperatures, allowing for a smaller required surface area A for the same heat duty Q. However, when the temperature difference at one end is equal to the other, the LMTD is simply that temperature difference. If one of the temperature differences is zero, the LMTD is mathematically undefined, but in practice, this represents a limit where heat transfer ceases to be effective. For more complex geometries like cross-flow or multi-pass shell-and-tube exchangers, a correction factor F is applied to the LMTD, such that [latex]\Delta T_{eff} = F \cdot \Delta T_{LM, counterflow}[/latex].
UNESCO Nomenclature: 3328
열역학
유형
추상 시스템
분열
점진적
용법
널리 사용됨
전구체
응용 프로그램
- design and performance analysis of shell and tube heat exchangers
- 산업용 보일러 및 응축기 크기 선정
- 냉난방 시스템 최적화
- 발전소의 열 관리
- 화학 공정 공학 계산
특허:
NA
잠재적 혁신 아이디어
- AI-driven optimization of multi-stage heat exchanger networks using real-time LMTD calculations
- development of compact heat exchangers with complex flow paths optimized via computational fluid dynamics to maximize the lmtd correction factor
- smart hvac systems that dynamically adjust fluid flow rates to maintain an optimal lmtd for energy efficiency
- miniaturized lmtd sensors for microfluidic heat exchangers in electronics cooling
- software for predicting and mitigating thermal stresses in exchangers based on lmtd profiles
- phase-change material (pcm) integrated heat exchangers where the lmtd model is adapted for 잠열 transfer periods
- self-cleaning heat exchangers that use controlled flow reversals to disrupt fouling, monitored by lmtd performance drops
- lmtd-based control algorithms for waste heat recovery systems in automotive applications
- 3d-printed heat exchangers with customized geometries designed to enhance the lmtd
- educational virtual reality simulations for demonstrating the impact of flow arrangements on the lmtd and overall efficiency
관련 용어: LMTD, 대수 평균 온도차, 열교환기, 열역학, 열전달, 역류, 병류, 열공학, 누셀트, 전체 열전달 계수.
역사적 맥락
로그 평균 온도 차이(LMTD)
(날짜를 알 수 없거나 관련이 없는 경우, 예를 들어 "유체역학"의 경우, 주목할 만한 등장 시기를 대략적으로 추정하여 제공합니다.)
